XR Test Refactor Part 3.2: Clean Up Asserts/Polls

Makes the following changes:
1. Changes runnables to lambdas
2. Changes all uses of Criteria to Criteria instead of Criteria<Boolean>
3. Adds failure statements to asserts and Criteria
4. Fixes failure statements that described the check condition, not the
   failure itself
5. Adds pollJavaScriptBooleanOrFail and changes uses of
   assertTrue(pollJavaScriptBoolean()) to it.

Bug: 863256
Change-Id: I7965fbf2f9d62199a9dbcf6f8040c2b71e5f1651
Reviewed-on: https://chromium-review.googlesource.com/1144410
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#576923}
26 files changed