tests: use packaging from setuptools instead of deprecated distutils
When invoking StrictVersion in 3.12 we got:
DeprecationWarning: distutils Version classes are deprecated. Use packaging.version instead.
distutils is dead in the standard library, and we have to move towards using
`setuptools` as general extern dependency. Instead of also requiring the extern
`packaging`, we will just use the packaging that is vendored in setuptools.
https://bz.mercurial-scm.org/1089
$ hg init repo
$ cd repo
$ mkdir a
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ hg ci -m m a
$ mkdir a b
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ cd b
Relative delete:
$ hg ci -m m ../a
$ cd ..