With 32-bit kTaggedSize string data address may not be kSystemPointerSize
aligned.

Bug: v8:7703
Change-Id: I243e6844bed62d96f8b07328fffe23e83512e8e5
Reviewed-on: https://chromium-review.googlesource.com/c/1481217Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59772}