run-tests: ignore failed removal of nonexistent installerrs When running tests with -j100 or so on a large machine, I see this os.remove call failing semi-regularly. Since it's not really a problem when the file is already gone, just suppress the error in that case.

templater: move verbosity-to-template matcher to constructor We're going to reuse this and it's silly for it to be done per-cset anyway.

templater: remove pseudo-ternary

templater: fix variable name that shadows built-in

templater: minor whitespace tweaks

lock: make trylock private

lock: loop a finite number of times in trylock (issue4787) ..before falling back to lock, which will sleep. This only addresses the CPU consumption of the reported issue.