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

compiler/testData/codegen/light-analysis/lazyCodegen/increment.txt

@@ -1,3 +1,4 @@
+@kotlin.Metadata
 public final class A {
     private final field p: int
     private @org.jetbrains.annotations.NotNull field prop: A
@@ -8,6 +9,7 @@ public final class A {
     public final method setProp(@org.jetbrains.annotations.NotNull p0: A): void
 }
 
+@kotlin.Metadata
 public final class IncrementKt {
     private static @org.jetbrains.annotations.NotNull field globalA: A
     private static @org.jetbrains.annotations.NotNull field holder: java.lang.String