Ignore design-time build value when debugging generator

This allows running F5 on the generator project and troubleshoot issues. By checking for an already attached debugger, we can debug also scenarios of code generation where the roslyn component starts it with DTB=true.

src/Orleans.CodeGenerator/Orleans.CodeGenerator.csproj

@@ -10,6 +10,7 @@
     <DevelopmentDependency>true</DevelopmentDependency>
     <IsOrleansFrameworkPart>false</IsOrleansFrameworkPart>
     <EnforceExtendedAnalyzerRules>true</EnforceExtendedAnalyzerRules>
+    <IsRoslynComponent>true</IsRoslynComponent>
   </PropertyGroup>
 
   <ItemGroup>

src/Orleans.CodeGenerator/OrleansSourceGenerator.cs

@@ -23,7 +23,8 @@ public void Execute(GeneratorExecutionContext context)
                     return;
                 }
 
-                if (context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.orleans_designtimebuild", out var isDesignTimeBuild)
+                if (!Debugger.IsAttached &&
+                    context.AnalyzerConfigOptions.GlobalOptions.TryGetValue("build_property.orleans_designtimebuild", out var isDesignTimeBuild)
                     && string.Equals("true", isDesignTimeBuild, StringComparison.OrdinalIgnoreCase))
                 {
                     return;

src/Orleans.CodeGenerator/Properties/launchSettings.json

@@ -0,0 +1,8 @@
+{
+  "profiles": {
+    "Roslyn": {
+      "commandName": "DebugRoslynComponent",
+      "targetProject": "..\\..\\test\\Orleans.Serialization.UnitTests\\Orleans.Serialization.UnitTests.csproj"
+    }
+  }
+}