Selector: Stop relying on CSS.supports( "selector(...)" )

Selector: Stop relying on CSS.supports( "selector(...)" )

`CSS.supports( "selector(...)" )` has different semantics than selectors passed
to `querySelectorAll`. Apart from the fact that the former returns `false` for
unrecognized selectors and the latter throws, `qSA` is more forgiving and
accepts some invalid selectors, auto-correcting them where needed - for
example, mismatched brackers are auto-closed. This behavior difference is
breaking for many users.

To add to that, a recent CSSWG resolution made `:is()` & `:where()` the only
pseudos with forgiving parsing; browsers are in the process of making `:has()`
parsing unforgiving.

Taking all that into account, we go back to our previous try-catch approach
without relying on `CSS.supports( "selector(...)" )`. The only difference
is we detect forgiving parsing in `:has()` and mark the selector as buggy.

The PR also updates `playwright-webkit` so that we test against a version
of WebKit that already has non-forgiving `:has()`.

Fixes gh-5194
Closes gh-5207
Ref gh-5206
Ref gh-5098
Ref gh-5107
Ref w3c/csswg-drafts#7676