MIPS32 doesn't have instructions to properly handle 64-bit atomic
instructions.

Skipping those test on MIPS64 simulator because they have flaky
TIMEOUT on buildbots.

Change-Id: I31511dfce70a933b9326a7c270509c5f31af743a
Reviewed-on: https://chromium-review.googlesource.com/c/1367450Reviewed-by: Stephan Herhut <herhut@chromium.org>
Commit-Queue: Predrag Rudic <prudic@wavecomp.com>
Cr-Commit-Position: refs/heads/master@{#58125}