[heap] Access wasted_memory() while holding lock

PagedSpace::RefillFreeList() needs to invoke wasted_memory()
while holding the lock. Otherwise this races with
PagedSpace::FreeLinearAllocationArea() which uses add_wasted_memory()
and already holds the lock.

Bug: v8:10315
Change-Id: I3a57191529cdd81d75833ec334a57f84a9a59194
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2428930Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70126}

src/heap/paged-spaces.cc

@@ -137,13 +137,14 @@ void PagedSpace::RefillFreeList() {
         owner->RefineAllocatedBytesAfterSweeping(p);
         owner->RemovePage(p);
         added += AddPage(p);
+        added += p->wasted_memory();
       } else {
         base::MutexGuard guard(mutex());
         DCHECK_EQ(this, p->owner());
         RefineAllocatedBytesAfterSweeping(p);
         added += RelinkFreeListCategories(p);
+        added += p->wasted_memory();
       }
-      added += p->wasted_memory();
       if (is_compaction_space() && (added > kCompactionMemoryWanted)) break;
     }
   }