Keep ImmutableLabelRemover under coreLibrarySupport enabled

- Reason: break //third_party/appreduce/integration_tests/inline_class_name/javatests:AndroidTests
- Investigation:
  Test fails even with no-op naming mapping change. e.g. unknown commit
  It is likely ClassRemapper still modifies the class file with an identical mapping configuration, and AppReduce depends on this semantic-identical but binary-different property. As this feature is for core library desugaring, limit the scope to core library for now.

PiperOrigin-RevId: 303917120
diff --git a/src/tools/android/java/com/google/devtools/build/android/desugar/Desugar.java b/src/tools/android/java/com/google/devtools/build/android/desugar/Desugar.java
index 21aa352..3b91d00 100644
--- a/src/tools/android/java/com/google/devtools/build/android/desugar/Desugar.java
+++ b/src/tools/android/java/com/google/devtools/build/android/desugar/Desugar.java
@@ -1015,9 +1015,9 @@
       InvocationSiteTransformationRecordBuilder callSiteRecord) {
     ClassVisitor visitor = checkNotNull(writer);
 
-    visitor = new ImmutableLabelRemover(visitor);
 
     if (coreLibrarySupport != null) {
+      visitor = new ImmutableLabelRemover(visitor);
       visitor = new EmulatedInterfaceRewriter(visitor, coreLibrarySupport);
       visitor = new CorePackageRenamer(visitor, coreLibrarySupport);
       visitor = new CoreLibraryInvocationRewriter(visitor, coreLibrarySupport);