Kapt3: Write stub class files with metadata (needed for incremental compilation)

compiler/testData/codegen/light-analysis/callableReference/function/enumValueOfMethod.txt

@@ -1,3 +1,4 @@
+@kotlin.Metadata
 public enum class E {
     public final static field ENTRY: E
     protected method <init>(p0: java.lang.String, p1: int): void
@@ -5,6 +6,7 @@ public enum class E {
     public static method values(): E[]
 }
 
+@kotlin.Metadata
 public final class EnumValueOfMethodKt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
 }