run-tests: cleanup windows generation of the python / python3 pointeur
They are no need to generate then in RUNTESTDIR and we don't need a python2
executable. (because not test ever use `python2` explicitly).
This is probably still not perfect, but at least it is better.
Differential Revision: https://phab.mercurial-scm.org/D11045
#require execbit
$ hg init repo
$ cd repo
$ echo foo > foo
$ chmod 644 foo
$ hg ci -qAm '644'
$ chmod 755 foo
$ hg ci -qAm '755'
reverting to rev 0
$ hg revert -a -r 0
reverting foo
$ hg st
M foo
$ hg diff --git
diff --git a/foo b/foo
old mode 100755
new mode 100644
$ cd ..