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

compiler/testData/codegen/light-analysis/reflection/kClassInAnnotation/basic.txt

@@ -1,18 +1,22 @@
 @kotlin.annotation.Retention
 @java.lang.annotation.Retention
+@kotlin.Metadata
 public annotation class Ann {
     public abstract method arg(): java.lang.Class
 }
 
+@kotlin.Metadata
 public final class BasicKt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
 }
 
 @Ann
+@kotlin.Metadata
 public final class MyClass {
     public method <init>(): void
 }
 
+@kotlin.Metadata
 public final class OK {
     public method <init>(): void
 }