All the PR test sites are missing the civicrm_strip_non_numeric function
So for example just edit a contact with a phone and save it -> crash.
But it doesn't seem to be a problem on dmaster.demo and I can't reproduce this doing a "normal" install, so I think it's something about how the PR test sites get built. Maybe they just need to do a cache rebuild at the end.
It's from the below PR so marking a regression but it's not the usual type of regression, but if some people do installs the same way the PR test sites do then they might see it.