persistent-nodemap: add a way to make the picked uid predictable This will make the test less volatile and therefore easier to maintain. I am setting this is for the persistent nodemap docket first, but my target is to use similar logic for the revlogv2 (and co) test. For persisent nodemap, they are too many different in how each test variants (with rust, without rust, etc) needs new uid for this be really useful (right now). However it will be directly useful for the revlogv2 logic. Differential Revision: https://phab.mercurial-scm.org/D10753

run-tests: disable color in 'auto' mode on Windows if stdout is redirected Differential Revision: https://phab.mercurial-scm.org/D10761

run-tests: enable color on Windows In setting up the CI for Windows on heptapod, I noticed it was complaining about color not being enabled because pygments wasn't installed- even though it was. I had initially disabled color on Windows when using Windows 7, because that didn't understand ANSI color codes and made a mess of the output. But now that it's been unsupported for over a year, I don't think we should care about it either. It's admittedly a hack to depend on Mercurial proper to enable color support in the terminal, but I didn't feel like duplicating that code. I'm under the impression that 3rd party stuff is supposed to use this runner in the Mercurial repo instead of using their own copy, so I think it's safe to assume the Mercurial code is available. If it's not, it won't break anything. Differential Revision: https://phab.mercurial-scm.org/D10760

transaction: trivial refactoring Differential Revision: https://phab.mercurial-scm.org/D10714