Drive-by-fix:
- Add CSA::LoadElementsKind helper

Bug: v8:7796
Change-Id: Icbf81effdd42efa7f8ec56f8d1a40c331c7a25e4
Reviewed-on: https://chromium-review.googlesource.com/1078849
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53472}