This removes duplication in the platform-dependent assemblers by
introducing {AssemblerBase::ShouldRecordRelocInfo}.
On arm64, we also remove a bool and replace it by an early exit.

R=mstarzinger@chromium.org

Bug: v8:8238
Change-Id: I08c623a19167a358c3188dc9008f045120da82b1
Reviewed-on: https://chromium-review.googlesource.com/1251085Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56319}