This patch introduces 109 "#smoke" tests - a subset of tests that makes
sure that basic Playwright functionality works. This set is loosely
defined; feel free to add/remove tests to the set. The only goal is to
keep this set minimal & fast to run.
I tried to pick tests so that various parts of Playwright functionality
are exercised.
This patch moves service tests to use experimental grid.
Test changes:
- `proxy.spec.ts` - proxy setup is not supported at all in service mode.
This is because we already use proxy for browsers to properly resolve
localhost.
- `har.spec.ts` - tests disabled since connection port is different.
