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

compiler/testData/codegen/light-analysis/reflection/mapping/constructor.txt

@@ -1,25 +1,30 @@
+@kotlin.Metadata
 public final class ConstructorKt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
     public final static method check(@org.jetbrains.annotations.NotNull p0: kotlin.reflect.KFunction): void
 }
 
+@kotlin.Metadata
 public final class K {
     inner class K/Inner
     inner class K/Nested
     public method <init>(): void
 }
 
+@kotlin.Metadata
 public final class K/Inner {
     synthetic final field this$0: K
     inner class K/Inner
     public method <init>(p0: K): void
 }
 
+@kotlin.Metadata
 public final static class K/Nested {
     inner class K/Nested
     public method <init>(): void
 }
 
+@kotlin.Metadata
 public final class Secondary {
     public method <init>(p0: int): void
 }