perf: add a --rev attribute to perfindex This allow for benchmarking the time necessary to look for other version than the tip.

perf: update perfindex to be more realistic The previous code was creating a revlog manually, we now use the actual `localrepo` method to create it. We have to jump though extra hops to work around the impact of filecache.

match: drop unnecessary wrapping of regex in group It seems the regexes have been wrapped in an unnamed group since b6c42714d900 (Add locate command., 2005-07-05). In that commit, the grouping was needed because there was a "head" ('^') added before the group and a "tail" (os.sep) added after it. It seems the head was moved inside the group in 1c0c413cccdd (Get add and locate to use new repo and dirstate walk code., 2005-07-18) and the tail was moved inside the group in 89985a1b3427 (Clean up walk and changes code to use normalised names properly., 2005-07-31), So it seems to me that we've carried around the unnecessary group for 13 years. This patch removes it. Differential Revision: https://phab.mercurial-scm.org/D5352

match: use _BASE_SIZE instead of magic value 4 Differential Revision: https://phab.mercurial-scm.org/D5351