Set global proxy internal field count based on the global object template.

test/cctest/test-serialize.cc

Index: test/cctest/test-serialize.cc
diff --git a/test/cctest/test-serialize.cc b/test/cctest/test-serialize.cc
index dd0a101bbc044e947ba1de78c82ae64fae5ffdf7..36510aa3e30ba59e835ab3afe9fe8db439980bcf 100644
--- a/test/cctest/test-serialize.cc
+++ b/test/cctest/test-serialize.cc
@@ -416,7 +416,8 @@ UNINITIALIZED_TEST(PartialSerializerContext) {
     HandleScope handle_scope(isolate);
     Handle<Object> root;
     Handle<JSGlobalProxy> global_proxy =
-        isolate->factory()->NewUninitializedJSGlobalProxy();
+        isolate->factory()->NewUninitializedJSGlobalProxy(
+            JSGlobalProxy::SizeFor(0));
     {
       SnapshotData snapshot_data(partial_blob);
       Deserializer deserializer(&snapshot_data);
@@ -535,7 +536,8 @@ UNINITIALIZED_TEST(PartialSerializerCustomContext) {
     HandleScope handle_scope(isolate);
     Handle<Object> root;
     Handle<JSGlobalProxy> global_proxy =
-        isolate->factory()->NewUninitializedJSGlobalProxy();
+        isolate->factory()->NewUninitializedJSGlobalProxy(
+            JSGlobalProxy::SizeFor(0));
     {
       SnapshotData snapshot_data(partial_blob);
       Deserializer deserializer(&snapshot_data);