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

compiler/backend/src/org/jetbrains/kotlin/codegen/ClassBuilderMode.java

@@ -70,7 +70,7 @@ public class ClassBuilderMode {
      */
     public final static ClassBuilderMode KAPT3 = new ClassBuilderMode(
             /* bodies = */ false,
-            /* metadata = */ false,
+            /* metadata = */ true,
             /* sourceRetention = */ true,
             /* generateMultiFileFacadePartClasses = */ true);
 }

compiler/backend/src/org/jetbrains/kotlin/codegen/serialization/JvmSerializerExtension.java

@@ -164,7 +164,7 @@ public class JvmSerializerExtension extends SerializerExtension {
 
     @Override
     public void serializeErrorType(@NotNull KotlinType type, @NotNull ProtoBuf.Type.Builder builder) {
-        if (classBuilderMode == ClassBuilderMode.KAPT) {
+        if (classBuilderMode == ClassBuilderMode.KAPT || classBuilderMode == ClassBuilderMode.KAPT3) {
             builder.setClassName(stringTable.getStringIndex(TypeSignatureMappingKt.NON_EXISTENT_CLASS_NAME));
             return;
         }