heptapod-ci: add a script to map evolve branch to mercurial revision for tests map-hg-rev.sh can be tested using this command: ```sh for i in $(hg log -T '{branch}\n' | sort -u); do echo $i $(testlib/map-hg-rev.sh $i) done ```

{"pattern": "glob:hgext3rd/**/*.py", "tool": "byteify-strings"}