This is at least the second time I've seen this:
Build timed out (after 30 minutes)
https://integration.wikimedia.org/ci/job/mediawiki-extensions-php55/buildTimeTrend averages ~10 minutes. The php53 variant which is only run for older branches is even slower.
This was partly due to Scribunto being added to it (as part of T125050) which caused the test runtime to skyrocket (T126274).