[api] Do not force external GCs when only trying to synchronously process phantom callbacks

src/global-handles.cc

Index: src/global-handles.cc
diff --git a/src/global-handles.cc b/src/global-handles.cc
index 444614c166c0a0203e8af2b530215efecbcc54cf..fcf896fe5f5b766c409d96836078e34e257d8e3d 100644
--- a/src/global-handles.cc
+++ b/src/global-handles.cc
@@ -883,7 +883,9 @@ int GlobalHandles::PostGarbageCollectionProcessing(
   const int initial_post_gc_processing_count = ++post_gc_processing_count_;
   int freed_nodes = 0;
   bool synchronous_second_pass =
-      (gc_callback_flags & kGCCallbackFlagForced) != 0;
+      (gc_callback_flags &
+       (kGCCallbackFlagForced |
+        kGCCallbackFlagSynchronousPhantomCallbackProcessing)) != 0;
   freed_nodes += DispatchPendingPhantomCallbacks(synchronous_second_pass);
   if (initial_post_gc_processing_count != post_gc_processing_count_) {
     // If the callbacks caused a nested GC, then return.  See comment in