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

compiler/testData/codegen/light-analysis/callableReference/bound/multiCase.txt

@@ -1,3 +1,4 @@
+@kotlin.Metadata
 public final class A {
     private field v: int
     public method <init>(p0: int): void
@@ -6,6 +7,7 @@ public final class A {
     public final method setV(p0: int): void
 }
 
+@kotlin.Metadata
 public final class F {
     public final static field INSTANCE: F
     private static field u: int
@@ -14,6 +16,7 @@ public final class F {
     public final method setU(p0: int): void
 }
 
+@kotlin.Metadata
 public final class MultiCaseKt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
     public final static method g(@org.jetbrains.annotations.NotNull p0: A, p1: int): int