This unifies the RelocInfo::Visit method across architectures.

Bug: v8:8562
Change-Id: I36fdfb2f456aebb4d69977bb84727c9b49b22f69
Reviewed-on: https://chromium-review.googlesource.com/c/1456106
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59423}