This allows us to get rid a lot of the duplication of lines in LayoutTests/imported/w3c/resources/import-expectations.json, differing only by slashes.
<rdar://problem/113281074>
Pull request: https://github.com/WebKit/WebKit/pull/16330
Committed 266595@main (6d13b1672d0f): <https://commits.webkit.org/266595@main> Reviewed commits have been landed. Closing PR #16330 and removing active labels.