Use 124 max line length everywhere. Also, reduce tap max line length to
189 as Homebrew/homebrew-core has that as a maximum now. In future
Homebrew/homebrew-core will also be reduced to 124 maximum line length.
Remove pending tests that are never run on CI (i.e. require `--online`),
remove fixtures for those tests and just make `--official-cmd-taps`
run by `--online` instead.