[Android] Generate scripts at build time to run android tests.

Making changes so that at build time scripts will be generated that can be used to easily run tests.

BUG=490781
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1120883002

Cr-Commit-Position: refs/heads/master@{#332518}
32 files changed