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

compiler/testData/codegen/light-analysis/reflection/classes/companionObject.txt

@@ -1,18 +1,22 @@
+@kotlin.Metadata
 public final class A {
     public final static field C: A.C
     inner class A/C
     public method <init>(): void
 }
 
+@kotlin.Metadata
 public final static class A/C {
     inner class A/C
     private method <init>(): void
 }
 
+@kotlin.Metadata
 public final class CompanionObjectKt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
 }
 
+@kotlin.Metadata
 public enum class E {
     public final static field Companion: E.Companion
     public final static field ENTRY: E
@@ -22,6 +26,7 @@ public enum class E {
     public static method values(): E[]
 }
 
+@kotlin.Metadata
 public final static class E/Companion {
     inner class E/Companion
     private method <init>(): void