blink/css: Implement extended language ranges for :lang()

Following the CSS Selectors level 4 spec [1], this adds
support for using multiple language ranges in the :lang()
pseudo-class, separated by commas.

Matching an element’s content language to a language range
follows the extended filtering operation defined in
[RFC4647] Matching of Language Tags (section 3.3.2

[1]: https://www.w3.org/TR/selectors-4/#the-lang-pseudo
[2]: https://www.rfc-editor.org/rfc/rfc4647.html

Based on previous work by Roger Zanoni <rzanoni@igalia.com>

Bug: 40284975, 40811938
Change-Id: I11d17f7b9d3391642c13e8a2547a8ec7b59c2fd3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6677873
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Felipe Erias <felipeerias@igalia.com>
Cr-Commit-Position: refs/heads/main@{#1498726}