Rename LargeObjectIterator to LargeObjectSpaceObjectIterator.
Rename SemiSpaceIterator to SemiSpaceObjectIterator.
Rename CombinedHeapIterator to CombinedHeapObjectIterator.
Rename ReadOnlyHeapIterator to ReadOnlyHeapObjectIterator.
Rename HeapIterator to HeapObjectIterator.
Rename HeapObjectIterator to PagedSpaceObjectIterator.
Rename PagedSpaces to PagedSpaceIterator.

Bug: v8:9183
Change-Id: If4bd65d81e50bb45d207a897baaca8b723e4f10b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1645914Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Commit-Queue: Maciej Goszczycki <goszczycki@google.com>
Cr-Commit-Position: refs/heads/master@{#62217}