Introduce KotlinSyntheticClass annotation

Will be used instead of KotlinPackagePart, KotlinTraitImpl and other
hypothetical annotations we were planning to write on our synthesized classes
(lambdas, local functions, etc.)

core/runtime.jvm/src/kotlin/jvm/internal/KotlinSyntheticClass.java

@@ -20,6 +20,13 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 
 @Retention(RetentionPolicy.RUNTIME)
-public @interface KotlinPackagePart {
+public @interface KotlinSyntheticClass {
     int abiVersion();
+
+    Kind kind();
+
+    public static enum Kind {
+        PACKAGE_PART,
+        TRAIT_IMPL
+    }
 }

core/runtime.jvm/src/kotlin/jvm/internal/KotlinTraitImpl.java

@@ -1,25 +0,0 @@
-/*
- * Copyright 2010-2014 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package kotlin.jvm.internal;
-
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-
-@Retention(RetentionPolicy.RUNTIME)
-public @interface KotlinTraitImpl {
-    int abiVersion();
-}