run-tests: add substitution patterns for common '\' path output on Windows The goal is to reduce the amount of hand tuning of new/changed tests that is required on Windows. Since the OS prints the proper paths everywhere else, this is limited to Windows. These are based on the check-code rules that were dropped in 5feb782c7a95. There are some minor tweaks, because those were trying to detect '/' paths without a '(glob)' at the end, whereas these detect '\' paths. Also, it looks like the 'no changes made to subrepo' one was broke, because the path to the subrepo has been getting output but was not in the pattern. End anchors are dropped because '(glob)' is no longer required, but '(feature !)' annotations are a possibility. The 'saved backup bundle' pattern dropped from run-tests.py was simply carrying over the first capture group. The replace() method runs prior to evaluating '\1', but it wasn't doing anything because of the 'r' prefix on '\\'. The 'not recording move' entry is new, because I stumbled upon it searching for some of these patterns. There are probably others.

debuginstall: add a line about re2 availability Using re2 engine can massively speed up regexp. We make it simpler to check if it is available in a given install.

tests: fix the check-code rule for testing non-existent files I missed this in feecfefeba25.