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

compiler/testData/codegen/light-analysis/reflection/methodsFromAny/memberExtensionToString.txt

@@ -1,3 +1,4 @@
+@kotlin.Metadata
 public final class A {
     public method <init>(): void
     public final method foo(p0: int): double
@@ -5,6 +6,7 @@ public final class A {
     public final method setId(@org.jetbrains.annotations.NotNull p0: java.lang.String, @org.jetbrains.annotations.NotNull p1: java.lang.String): void
 }
 
+@kotlin.Metadata
 public final class MemberExtensionToStringKt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
 }