message: global_heap: check aboveMeshThreshold in meshing loop
  closes
diff: @@ -341,7 +341,7 @@ size_t GlobalHeap::meshSizeClassLocked(size_t sizeClass, MergeSetArray &mergeSet
  oneEmpty = true;
  }
  - if (!oneEmpty) {
  + if (!oneEmpty && !aboveMeshThreshold()) {
  meshLocked(dst, src);
  meshCount++;
  }
  