fuzz: try and ensure fuzzer tests run against the right python-config Also only under python 3. Differential Revision: https://phab.mercurial-scm.org/D9752

contrib: remove testing for `dirstate-tree` Rust feature This feature will be replaced in a few months, and served more as a proof-of-concept. Keeping it in CI when no one is using it anymore is just wasteful. Differential Revision: https://phab.mercurial-scm.org/D9716

perf: don't turn byte to string when formatting perfbranchmap I am not sure why this `str` all is there is the first place. Differential Revision: https://phab.mercurial-scm.org/D9751