Android: Invalidate test list cache properly for incremental test apks

Fixes test runner not noticing when you add / remove / rename tests.

Bug: 781357
Change-Id: I1f8b1d78670ee337277dac0a55fbc3e4fd1be879
Reviewed-on: https://chromium-review.googlesource.com/755854
Commit-Queue: agrieve <agrieve@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#514929}
2 files changed