Currently test_parser.py re-implements a bunch of the WPT manifest stuff; it shouldn't, it should just use the WPT manifest (or the code it uses). I did this when originally fixing Bug 263673, but we should probably land a smaller change for that bug first.
Pull request: https://github.com/WebKit/WebKit/pull/19554
<rdar://problem/118748827>
This landed months ago, linked to bug 263673: Committed 277673@main (b702871): https://commits.webkit.org/277673@main