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.
As of today, we can't navigate away from a page with beforeunload unless
we have an explicit `beforeunload` handler.
This patch updates our dialog auto-closing logic so that it auto-accepts
all beforeunload dialogs.
Fixes#8144
