This removes the last unconditional read accesses to the heap, but
required a significant refactoring.

- Remove HeapObjectRef::type().
- Change HeapObjectData::Is* testers to look at the instance type
  in HeapObjectData::map().

- Remove ObjectRef::oddball_type()
- Add MapRef::oddball_type()
- Add MapRef::is_undetectable().
- Add MapRef::is_callable().

- Remove JSHeapBroker::HeapObjectTypeFromMap()
- Remove Type::For(JSHeapBroker*, Handle<Map>)
- Add BitsetType::Lub(MapRef).
- Add Type::For(MapRef).
- Add Type::For(HeapObjectType).

- Add HeapObjectRef::GetHeapObjectType(). THIS IS TEMPORARY.

As the last item suggests, I couldn't actually remove the
HeapObjectType class yet. See the explanation in the code.

Bug: v8:7790
Change-Id: I508e4bd5337277b0050f2204392fc36f41032fe9
Reviewed-on: https://chromium-review.googlesource.com/1228033Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55994}