Revert of Add WeakMap to v8.h

src/runtime/runtime.h

Index: src/runtime/runtime.h
diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index 33852150d78b1b5d421e16be2c4791ff5522d41c..dca28f1ad44cba3d36fa5deae24263cf2af22b9d 100644
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -879,13 +879,6 @@
   MUST_USE_RESULT static MaybeHandle<Object> CreateArrayLiteralBoilerplate(
       Isolate* isolate, Handle<FixedArray> literals,
       Handle<FixedArray> elements);
-
-  static void WeakCollectionInitialize(
-      Isolate* isolate, Handle<JSWeakCollection> weak_collection);
-  static void WeakCollectionSet(Handle<JSWeakCollection> weak_collection,
-                                Handle<Object> key, Handle<Object> value);
-  static bool WeakCollectionDelete(Handle<JSWeakCollection> weak_collection,
-                                   Handle<Object> key);
 };