Move Mozilla-specific stuff out of the test runner.

--HG--
rename : testing/web-platform/harness/config.ini => testing/web-platform/config.ini
rename : testing/web-platform/harness/runtests.py => testing/web-platform/runtests.py
rename : testing/web-platform/harness/update.py => testing/web-platform/update.py
Fix mozlog tests for api change.