Optimize / Simplify HTMLFastPathParser::parseAttributes() a bit.
<rdar://problem/106239527>
Pull request: https://github.com/WebKit/WebKit/pull/11072
Committed 261237@main (b9f99e9eaaa0): <https://commits.webkit.org/261237@main> Reviewed commits have been landed. Closing PR #11072 and removing active labels.