Add 3 Macmini9,1 to Mac-BigSur-AppleSilicon-Debug-WK2
<rdar://problem/103122338>
Pull request: https://github.com/WebKit/WebKit/pull/7409
Committed 257647@main (5d27d796cbc7): <https://commits.webkit.org/257647@main> Reviewed commits have been landed. Closing PR #7409 and removing active labels.