c100p bots: put a bandaid on broken Thumb

BUG=skia:6471

CQ_INCLUDE_TRYBOTS=skia.primary:Test-ChromeOS-Clang-Chromebook_C100p-GPU-MaliT764-arm-Release,Test-ChromeOS-Clang-Chromebook_C100p-GPU-MaliT764-arm-Debug

Change-Id: I3faa28c69510fbb33d40abbfb59bf3a7ba5ddb77
Reviewed-on: https://skia-review.googlesource.com/13407
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
2 files changed