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

compiler/testData/codegen/light-analysis/privateConstructors/withLinkedClasses.txt

@@ -1,3 +1,4 @@
+@kotlin.Metadata
 public class Outer {
     private final @org.jetbrains.annotations.Nullable field p: Outer
     inner class Outer/First
@@ -6,12 +7,14 @@ public class Outer {
     public final @org.jetbrains.annotations.Nullable method getP(): Outer
 }
 
+@kotlin.Metadata
 public final class Outer/First {
     public final static field INSTANCE: Outer.First
     inner class Outer/First
     private method <init>(): void
 }
 
+@kotlin.Metadata
 public final static class Outer/Other {
     inner class Outer/Other
     public @synthetic.kotlin.jvm.GeneratedByJvmOverloads method <init>(): void
@@ -19,6 +22,7 @@ public final static class Outer/Other {
     public synthetic method <init>(p0: Outer, p1: int, p2: kotlin.jvm.internal.DefaultConstructorMarker): void
 }
 
+@kotlin.Metadata
 public final class WithLinkedClassesKt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
 }