Fix #18966: Upgrade various ERRORs to CRITICAL

[gsnedders]

All of these are cases where we abort the world, so they're kinda
critical I'd say.

Fixes #18966.

[jgraham]

I could argue some of these, but I guess the principle that there should always be a critical level message if we are about to exit with status != 0 is pretty sound.

[foolip]

This appears to have caused both Safari (#18995) and Edge (#19005) runs to start failing.

The underlying problem was presumably already there and uncovering it is good, but this change would have benefited from triggering full runs before landing on master. That would have avoided the need to rush to fix these issues.

At this point I don't think that reverting this is necessary, but if the Safari runs are still failing it might be the best way to recover.

[gsnedders]

@foolip I did do a full run of STP before landing, FWIW.

[foolip]

Weird, it seemed like a persistent failure. Perhaps the real cause for this snuck in in between your testing and landing? Can you check git log and see if anything stands out?