[heap] Bail out from incremental marking in embedder-tracer

This fixes DCHECK build with --noincremental-marking flag.

Change-Id: If1e8f9ec09bd91e628c3e92bbcd40f6960473f5b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1955598Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65374}

src/heap/embedder-tracing.cc

@@ -112,7 +112,7 @@ void LocalEmbedderHeapTracer::ProcessingScope::AddWrapperInfoForTesting(
 }
 
 void LocalEmbedderHeapTracer::StartIncrementalMarkingIfNeeded() {
-  if (!FLAG_global_gc_scheduling) return;
+  if (!FLAG_global_gc_scheduling || !FLAG_incremental_marking) return;
 
   Heap* heap = isolate_->heap();
   heap->StartIncrementalMarkingIfAllocationLimitIsReached(