Add v8::Object::CreationContext that works for a persistent handle

I need this API for https://codereview.chromium.org/1609343002/.

BUG=483722

Review-Url: https://codereview.chromium.org/1627233002
Cr-Commit-Position: refs/heads/master@{#39775}

include/v8.h

@@ -3220,6 +3220,12 @@ class V8_EXPORT Object : public Value {
    */
   Local<Context> CreationContext();
 
+  /** Same as above, but works for Persistents */
+  V8_INLINE static Local<Context> CreationContext(
+      const PersistentBase<Object>& object) {
+    return object.val_->CreationContext();
+  }
+
   /**
    * Checks whether a callback is set by the
    * ObjectTemplate::SetCallAsFunctionHandler method.