This patch:
- makes `npm run cunit/wunit/funit` and `npm run ctest/ftest/wtest` run
browser-specific tests only
- makes `npm run unit` and `npm run test` run *all* browser tests
- runs *all* our infrastructure tests as part of `npm run lint`
As a result, if there's one test to be tested across all three browsers,
you can focus it and do `npm run test`;
This patch re-implements matching and reporting for test runner.
Among other improvements:
- test failures now show a short snippet from test
- test failures now explicitly say what received and what was expected
- `expect.toBe()` now does text diff when gets strings as input
- `expect.toEqual` now does object diff
disables some failing Firefox tests
Moves newContext error checking before the context is created, to not create zombie contexts
sets CI timeout to 30 seconds
waits for `exit` instead of `close` for processes
