procutil: unroll uin/uout loop in protectstdio() I'll change uout to be redirected to stderr.

context: drop support for changeid of type long (API?) I don't see a reason to support type long. It's pretty much the same type as int. There was some discussion about it on the mailing list around the time of ff2f90503d64 (context: work around `long` not existing on Python 3, 2017-03-11), but I couldn't find a good reason to keep it. There was some mention of hgtk doing "repo[long(rev)]", but that was in 2012. Differential Revision: https://phab.mercurial-scm.org/D2989