test: migrate config-precedence tests
Copies the config-precedence tests from prettier.
@fabiospampinato i could do with some help here. i haven't updated the snapshots yet since some of them are legitimate failures it seems (until we decide what to do)
basically seems like one or more of the tests expect CLI args to be overridden by config files, but we do the opposite
I just checked the history, it's added in https://github.com/prettier/prettier/pull/2733 with lots of questions, basically, it was added only because someone may use the CLI without a config file.
I highly doubt anyone using it nowadays.
@fisker Should we just delete the --config-precedence flag then?
I agree to remove it. CLI flags should always take higher precedence.
Removed support in c90b4e4, so I'm closing this.