Merge to XFA: Run javascript/pixel tests via automated script.

This pulls in:
7435e8e Run pixel tests via automated script.
83c87e5 run_javascript_tests.py: Be more flexible about directory layout.
5898509 Test top-level Document JS properties.
9f93baf Create run_javascript_tests.py

TBR=thestig@chromium.org

Review URL: https://codereview.chromium.org/923293002
9 files changed