Tests are failing on MIPS with bus error because instruction cache is not flushed.

Change-Id: I1725a87ea2dc36ffde767d10a0c4deea0e069c09
Reviewed-on: https://chromium-review.googlesource.com/950722Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Ivica Bogosavljevic <ivica.bogosavljevic@mips.com>
Cr-Commit-Position: refs/heads/master@{#51768}