Right now we test PHPUnit, npm, and selenium tests from all gated extensions against all changes, but we don't do the same for phan, which means changes like https://gerrit.wikimedia.org/r/c/mediawiki/core/+/701074 can break the build for gated extensions.
We can fix this by adding (yet another) job running this change with all the other gated extensions together in the gate-and-submit branch, like we do with the 'wmf-quibble' jobs.