It makes no sense to check if unaligned accesses of bytes in memory are
allowed, since these accesses are always aligned. There was a problem
on mips that we created an UnalignedLoad(Int8), which was, however, not
implemented in the mips instruction selector.

R=clemensh@chromium.org

Change-Id: I20369e078e3c24942aa90c2bd3333d9881de0072
Reviewed-on: https://chromium-review.googlesource.com/463006Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44277}