Gradle 5.1 breaks Jukito's @All when using JUnit 5 useJUnitPlatform

[slayful]

Here's a minimal failing project: https://github.com/slayful/minimal-jukito-gradle-5.1-failing-project
I'm suspecting there's an issue when generating test cases or their names, maybe.
Here's the stack trace with the issue.

java.lang.AssertionError
	at org.gradle.api.internal.tasks.testing.processors.TestOutputRedirector.setOutputOwner(TestOutputRedirector.java:49)
	at org.gradle.api.internal.tasks.testing.processors.CaptureTestOutputTestResultProcessor.completed(CaptureTestOutputTestResultProcessor.java:80)
	at org.gradle.api.internal.tasks.testing.results.AttachParentTestResultProcessor.completed(AttachParentTestResultProcessor.java:56)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.actor.internal.DefaultActorFactory$BlockingActor.dispatch(DefaultActorFactory.java:122)
	at org.gradle.internal.actor.internal.DefaultActorFactory$BlockingActor.dispatch(DefaultActorFactory.java:97)
	at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
	at com.sun.proxy.$Proxy3.completed(Unknown Source)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestExecutionListener.executionFinished(JUnitPlatformTestExecutionListener.java:110)
	at org.junit.platform.launcher.core.TestExecutionListenerRegistry$CompositeTestExecutionListener.lambda$executionFinished$5(TestExecutionListenerRegistry.java:92)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
	at org.junit.platform.launcher.core.TestExecutionListenerRegistry.notifyTestExecutionListeners(TestExecutionListenerRegistry.java:59)
	at org.junit.platform.launcher.core.TestExecutionListenerRegistry.access$100(TestExecutionListenerRegistry.java:28)
	at org.junit.platform.launcher.core.TestExecutionListenerRegistry$CompositeTestExecutionListener.executionFinished(TestExecutionListenerRegistry.java:92)
	at org.junit.platform.launcher.core.ExecutionListenerAdapter.executionFinished(ExecutionListenerAdapter.java:56)
	at org.junit.vintage.engine.execution.RunListenerAdapter.fireExecutionFinished(RunListenerAdapter.java:202)
	at org.junit.vintage.engine.execution.RunListenerAdapter.testFinished(RunListenerAdapter.java:160)
	at org.junit.vintage.engine.execution.RunListenerAdapter.testFinished(RunListenerAdapter.java:76)
	at org.junit.runner.notification.SynchronizedRunListener.testFinished(SynchronizedRunListener.java:56)
	at org.junit.runner.notification.RunNotifier$7.notifyListener(RunNotifier.java:190)
	at org.junit.runner.notification.RunNotifier$SafeNotifier.run(RunNotifier.java:72)
	at org.junit.runner.notification.RunNotifier.fireTestFinished(RunNotifier.java:187)
	at org.junit.internal.runners.model.EachTestNotifier.fireTestFinished(EachTestNotifier.java:38)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:331)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.jukito.JukitoRunner.run(JukitoRunner.java:227)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
	at org.junit.vintage.engine.execution.RunnerExecutor.execute(RunnerExecutor.java:39)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
	at java.base/java.util.Iterator.forEachRemaining(Iterator.java:133)
	at java.base/java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
	at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
	at org.junit.vintage.engine.VintageTestEngine.executeAllChildren(VintageTestEngine.java:79)
	at org.junit.vintage.engine.VintageTestEngine.execute(VintageTestEngine.java:70)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:220)
	at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:188)
	at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:202)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:181)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:102)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$000(JUnitPlatformTestClassProcessor.java:82)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:78)
	at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:61)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)
	at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
	at com.sun.proxy.$Proxy2.stop(Unknown Source)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.stop(TestWorker.java:132)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:175)
	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:157)
	at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:404)
	at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
	at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
	at java.base/java.lang.Thread.run(Thread.java:834)