[heap] Scavenger: Remove dead code

Bug: chromium:738865
Change-Id: Ia9544707d4117187746fc50a416370b3c08ab842
Reviewed-on: https://chromium-review.googlesource.com/593313Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46993}

src/heap/heap.cc

@@ -1940,10 +1940,6 @@ void Heap::Scavenge() {
   isolate()->global_handles()->IdentifyWeakUnmodifiedObjects(
       &JSObject::IsUnmodifiedApiObject);
 
-  std::vector<MemoryChunk*> pages;
-  RememberedSet<OLD_TO_NEW>::IterateMemoryChunks(
-      this, [&pages](MemoryChunk* chunk) { pages.push_back(chunk); });
-
   {
     // Copy roots.
     TRACE_GC(tracer(), GCTracer::Scope::SCAVENGER_ROOTS);