py3: make contrib/debugshell.py work with Python 3 I changed default mercurial installation of my personal laptop to one installed with python 3.7. debugshell is one of the extension which I have enabled and it was failing. This patch makes debugshell works with Python 3. I found that chg does not work with python 3. Differential Revision: https://phab.mercurial-scm.org/D6031

absorb: let scmutil.cleanupnodes() take care of setting phase Differential Revision: https://phab.mercurial-scm.org/D6036

absorb: use scmutil.cleanupnodes() also when obsmarkers are disabled A side-effect of this is the new warning in the test case, but the warning is valid, so I don't think that's a problem. Differential Revision: https://phab.mercurial-scm.org/D6035

absorb: use scmutil.cleanupnodes() so operation gets set The operation is useful for e.g. `hg obslog` output. Differential Revision: https://phab.mercurial-scm.org/D6034

test: follow-up on 1c4d6ab2ecb8, stabilize test-remotefilelog-bgprefetch.t In 1c4d6ab2ecb8, I've added some sleeps after about half of the calls to `hg debugwaitonrepack` but it seems the other calls are also flaky as catched by our CI: https://ci.octobus.net/job/MercurialPy2/299/console. Add sleeps after all calls in order to be safe.

tests: add more wildcards to test-extdiff.t This test has been flakey recently on Windows, but it appears to be the same scenario as 88d4477ac4f6.