[ews] layout-test can go in infinite retry loop for branch PRs if there are 30+ failures on that branch. e.g.: https://ews-build.webkit.org/#/builders/70/builds/18105 https://ews-build.webkit.org/#/builders/70/builds/18066 https://ews-build.webkit.org/#/builders/70/builds/18034 https://ews-build.webkit.org/#/builders/70/builds/18013 https://ews-build.webkit.org/#/builders/70/builds/17987 https://ews-build.webkit.org/#/builders/70/builds/17950
<rdar://problem/101426255>
Note that we handle similar problem with build failure on builder queues on branch in https://bugs.webkit.org/show_bug.cgi?id=246147 by failing the build. There were discussions for doing similar thing for testers, but there were different opinions (as there are pros and cons of that approach) and there wasn't an agreement to use that approach for tester queues. (Slack discussion link in radar)