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

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

@@ -1,3 +1,4 @@
+@kotlin.Metadata
 public final class A {
     public final static field Companion: A.Companion
     inner class A/Companion
@@ -7,27 +8,32 @@ public final class A {
     public method <init>(): void
 }
 
+@kotlin.Metadata
 public final static class A/Companion {
     inner class A/Companion
     private method <init>(): void
 }
 
+@kotlin.Metadata
 public final class A/Inner {
     synthetic final field this$0: A
     inner class A/Inner
     public method <init>(p0: A): void
 }
 
+@kotlin.Metadata
 public final static class A/Nested {
     inner class A/Nested
     public method <init>(): void
 }
 
+@kotlin.Metadata
 private final static class A/PrivateNested {
     inner class A/PrivateNested
     public method <init>(): void
 }
 
+@kotlin.Metadata
 public final class NestedClassesKt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
     public final static @org.jetbrains.annotations.NotNull method nestedNames(@org.jetbrains.annotations.NotNull p0: kotlin.reflect.KClass): java.util.List