Fetch global object from jsproxy prototype instead of embedding it in StoreGlobal.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index a0ffd129c309a3a5a7a7f6764829ecad1562579c..f8009a2697428b0241558a77015080b98000f1e0 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -1092,8 +1092,8 @@ class StoreGlobalStub : public HandlerStub {
                                        Handle<PropertyCell> cell) {
     if (check_global()) {
       Code::FindAndReplacePattern pattern;
-      pattern.Add(Handle<Map>(global_placeholder(isolate())->map()), global);
-      pattern.Add(isolate()->factory()->meta_map(), Handle<Map>(global->map()));
+      pattern.Add(isolate()->factory()->meta_map(),
+                  Map::WeakCellForMap(Handle<Map>(global->map())));
       pattern.Add(isolate()->factory()->global_property_cell_map(), cell);
       return CodeStub::GetCodeCopy(pattern);
     } else {