Add unit-test in AnalyzeCompileWebKitResults for branch PR scenario.
For https://bugs.webkit.org/show_bug.cgi?id=246147
Pull request: https://github.com/WebKit/WebKit/pull/5091
Committed 255227@main (49a5b47c7111): <https://commits.webkit.org/255227@main> Reviewed commits have been landed. Closing PR #5091 and removing active labels.
<rdar://problem/100859724>