Most tests passed with an extra argument to explicitly enable the pass.
One does not, deleted it as part of this change. I can't see why the codegen
would be different between default on and default off but switched on. It
can be retrieved from the project history.
This would be a revert, but git revert was not clean. Disabling the pass
and leaving it in tree is less likely to cause breakage elsewhere than
patching up the git revert conflicts on unfamiliar code. It'll be landed
without review, as @hsmhsm is believed unavailable at present.