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

compiler/testData/codegen/light-analysis/delegatedProperty/topLevelVar.txt

@@ -1,3 +1,4 @@
+@kotlin.Metadata
 public final class Delegate {
     private field inner: int
     public method <init>(): void
@@ -7,6 +8,7 @@ public final class Delegate {
     public final method setValue(@org.jetbrains.annotations.Nullable p0: java.lang.Object, @org.jetbrains.annotations.NotNull p1: kotlin.reflect.KProperty, p2: int): void
 }
 
+@kotlin.Metadata
 public final class TopLevelVarKt {
     private synthetic final static field $$delegatedProperties: kotlin.reflect.KProperty[]
     private final static @org.jetbrains.annotations.NotNull field prop$delegate: Delegate