Revert of Fix IsWeakObjectInOptimizedCode predicate to also include property...

Revert of Fix IsWeakObjectInOptimizedCode predicate to also include property cells. (patchset #1 id:1 of https://codereview.chromium.org/909123002/)

Reason for revert:
Seems to fail several slow asserts (not on the try server):
http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20debug/builds/1841

Original issue's description:
> Fix IsWeakObjectInOptimizedCode predicate to also include property cells.
>
> BUG=v8:3882
> LOG=NO
>
> Committed: https://crrev.com/f8c404849dd01b538e52d95412225c06a0101808
> Cr-Commit-Position: refs/heads/master@{#26549}

TBR=dcarney@chromium.org,ulan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:3882

Review URL: https://codereview.chromium.org/909973004

Cr-Commit-Position: refs/heads/master@{#26551}

src/objects-inl.h

@@ -5242,9 +5242,7 @@ bool Code::IsWeakObjectInOptimizedCode(Object* object) {
     return Map::cast(object)->CanTransition() &&
            FLAG_weak_embedded_maps_in_optimized_code;
   }
-  if (object->IsCell() || object->IsPropertyCell()) {
-    object = Cell::cast(object)->value();
-  }
+  if (object->IsCell()) object = Cell::cast(object)->value();
   if (object->IsJSObject()) {
     return FLAG_weak_embedded_objects_in_optimized_code;
   }