[heap] Don't reset objects_size_ counter before freeing new LOs.

Bug: chromium:852420
Change-Id: I12cac5981cbb2af1c1bd150bfb5fcec028e8876d
Reviewed-on: https://chromium-review.googlesource.com/c/1352297Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57882}

src/heap/spaces.cc

@@ -3752,7 +3752,6 @@ void NewLargeObjectSpace::Flip() {
 
 void NewLargeObjectSpace::FreeAllObjects() {
   LargePage* current = first_page();
-  objects_size_ = 0;
   while (current) {
     LargePage* next_current = current->next_page();
     Unregister(current, static_cast<size_t>(current->GetObject()->Size()));