Revert "Chromedriver: Make test runner emit proper test results"

This reverts commit 9b237478.

Reason for revert: Seems to have broken the test suite, see https://crbug.com/855290

Original change's description:
> Chromedriver: Make test runner emit proper test results
> 
> The chrome test result format needs failed tests to be marked as
> unexpected to be recognized as true failures. Otherwise they're thought
> to be acceptable failures, and don't show up as actual failures when
> parsed.
> 
> Bug: 533481
> Change-Id: Ica94a18a4503a5553ef5602627643ae526155e1a
> Reviewed-on: https://chromium-review.googlesource.com/1109269
> Reviewed-by: John Chen <johnchen@chromium.org>
> Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
> Commit-Queue: Stephen Martinis <martiniss@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#569341}

TBR=martiniss@chromium.org,crouleau@chromium.org,johnchen@chromium.org

Change-Id: Iac8dfd494895bfa0e5c786bda43d43036f494f73
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 533481
Reviewed-on: https://chromium-review.googlesource.com/1111357Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Commit-Queue: Stephen Martinis <martiniss@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569474}

chrome/test/chromedriver/test/run_py_tests.py

@@ -2974,7 +2974,6 @@ if __name__ == '__main__':
 
     for failure in result.failures + result.errors:
       output['tests'][failure[0].id()]['actual'] = 'FAIL'
-      output['tests'][failure[0].id()]['unexpected'] = True
 
     num_fails = len(result.failures) + len(result.errors)
     output['num_failures_by_type']['FAIL'] = num_fails