`IsHoleyElementsKind` doesn’t just check for holeyness — it checks for
dictionary elements as well. Its name should reflect that.

This patch renames `IsHoleyElementsKind` to
`IsHoleyOrDictionaryElementsKind`, which makes it possible to rename
`IsFastHoleyElementsKind` to `IsHoleyElementsKind` in a future patch.

R=jkummerow@chromium.org, cbruni@chromium.org
BUG=v8:6548

Change-Id: Id799fe396442e9810426145359254d60990f8492
Reviewed-on: https://chromium-review.googlesource.com/558344Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46367}