[heap] Do not delay mark-compact in Heap::CollectGarbage if incremental

marking needs finalization.

TBR=mlippautz@chromium.org
BUG=chromium:671994,chromium:670675

Review-Url: https://codereview.chromium.org/2560813002
Cr-Commit-Position: refs/heads/master@{#41558}

src/heap/heap.cc

@@ -962,6 +962,7 @@ bool Heap::CollectGarbage(GarbageCollector collector,
       !ShouldFinalizeIncrementalMarking() && !ShouldAbortIncrementalMarking() &&
       !incremental_marking()->IsStopped() &&
       !incremental_marking()->should_hurry() &&
+      !incremental_marking()->NeedsFinalization() &&
       !IsCloseToOutOfMemory(new_space_->Capacity())) {
     if (!incremental_marking()->IsComplete() &&
         !mark_compact_collector()->marking_deque()->IsEmpty() &&