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

compiler/testData/codegen/light-analysis/toArray/toArray.txt

@@ -1,3 +1,4 @@
+@kotlin.Metadata
 public final class MyCollection {
     private final @org.jetbrains.annotations.NotNull field delegate: java.util.Collection
     public method <init>(@org.jetbrains.annotations.NotNull p0: java.util.Collection): void
@@ -18,6 +19,7 @@ public final class MyCollection {
     public method toArray(p0: java.lang.Object[]): java.lang.Object[]
 }
 
+@kotlin.Metadata
 public final class ToArrayKt {
     public final static @org.jetbrains.annotations.NotNull method box(): java.lang.String
 }