But does not change to xenial for test using armv7l cpu.

Bug: chromium:954890
Change-Id: I02268f469001f197210cde9c63804a3dcea06a7f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1687831
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62531}