Drive-by: Fix a few BE related issue with ptr-compr enabled.

Change-Id: Ic2ff9e69a42e65089a1c1544e5eba1833c2fd95e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2057355Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#66926}