[Test Automation] ExecuteJs[At], CheckJs[At] fail on error

Previously, ExecuteJs, ExecuteJsAt, CheckJs, and CheckJsAt could swallow
relevant error information if an exception was thrown, or (in the case
of the ...At() versions) if the element was not present.

This rewrites the JS injection logic for these methods so that all
errors are caught and explicitly surfaced as test failures, with their
JS error messages. This includes any of:
 - DeepQuery path not found
 - Exception thrown by injected function
 - Injected function returns a promise which then calls 'reject'

In order to handle the case where executed JS may destroy or navigate the current web page, an optional "fire and forget" mode is added to ExecuteJs[At] which preserves the old behavior (though you will not get error checking in that case).

Numerous tests ensuring functionality are also added.

Bug: 1478691

Change-Id: Ibbd0d713e4dad7783958107943e2abc934bc30ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4846076
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Dana Fried <dfried@chromium.org>
Auto-Submit: Dana Fried <dfried@chromium.org>
Reviewed-by: Taylor Bergquist <tbergquist@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1195627}