[heap] Skip PublishPendingAllocations for TPH

TPH doesn't support multiple mutators at the moment, so concurrent_inlining is disabled.
Thus we don't need to support `PublishPendingAllocations` for now.

Bug: v8:11641
Change-Id: I26f63f4093027878563c15de594a0a6bbef31c0a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2849819
Commit-Queue: Wenyu Zhao <wenyu.zhao@anu.edu.au>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74213}

src/heap/heap.cc

@@ -995,6 +995,7 @@ void Heap::RemoveAllocationObserversFromAllSpaces(
 }
 
 void Heap::PublishPendingAllocations() {
+  if (FLAG_enable_third_party_heap) return;
   new_space_->MarkLabStartInitialized();
   PagedSpaceIterator spaces(this);
   for (PagedSpace* space = spaces.Next(); space != nullptr;