While this situation sounds somewhat exotic, it's a relatively common situation in cloud hosted infrastructure. Build scripts, in particular, are things that can easily (accidently) run multiple autoinstallers in parallel when running on a fresh system.
<rdar://problem/109488201>
Pull request: https://github.com/WebKit/WebKit/pull/13994
Committed 264322@main (caf109704d37): <https://commits.webkit.org/264322@main> Reviewed commits have been landed. Closing PR #13994 and removing active labels.
Committed 259548.770@safari-7615-branch (aa5e9d582edd): <https://commits.webkit.org/259548.770@safari-7615-branch> Reviewed commits have been landed. Closing PR #605 and removing active labels.