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

compiler/testData/codegen/light-analysis/properties/kt8928.txt

@@ -1,3 +1,4 @@
+@kotlin.Metadata
 public final class App {
     public final static field Companion: App.Companion
     private static @org.jetbrains.annotations.NotNull field s: java.lang.String
@@ -6,6 +7,7 @@ public final class App {
     public final method init(): void
 }
 
+@kotlin.Metadata
 public final static class App/Companion {
     inner class App/Companion
     private method <init>(): void
@@ -13,6 +15,7 @@ public final static class App/Companion {
     private final method setS(p0: java.lang.String): void
 }
 
+@kotlin.Metadata
 public final class Kt8928Kt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
 }