Deprecate using build_cuda_plugin_from_source flag and rely on jaxlib…

…_build config.

If jaxlib needs to be built from source, cuda plugin will be built from source as well.

PiperOrigin-RevId: 660926791

jaxlib/jax.bzl

@@ -267,10 +267,10 @@ def jax_test(
             deps = [
                 "//jax",
                 "//jax:test_util",
-            ] + deps + if_building_jaxlib(["//jaxlib/cuda:gpu_only_test_deps"]) + select({
-                "//jax:enable_build_cuda_plugin_from_source": ["//jax_plugins:gpu_plugin_only_test_deps"],
-                "//conditions:default": [],
-            }),
+            ] + deps + if_building_jaxlib([
+                "//jaxlib/cuda:gpu_only_test_deps",
+                "//jax_plugins:gpu_plugin_only_test_deps",
+            ]),
             data = data,
             shard_count = test_shards,
             tags = test_tags,