tests: blacklist a handful of test with `rhg` or `chg` The use of `alias` to enforce `chg` and `rhg` means we are actually using a mix of `rhg`/`chg` and `hg` when calling `hg` in the test. Fixing this breaks various tests. This would be a large detour to fix that. I am disabling them for now with an appropriate comment. We would hopefully get back to them by the 5.8 release. Differential Revision: https://phab.mercurial-scm.org/D11052