[PATCH 2 of 3 py3 v3] tests: make a variable for hg binary location in test-check-py3-commands

[Augie Fackler]

> On Mar 13, 2017, at 13:30, Gregory Szorc <gregory.szorc at gmail.com> wrote:
> 
> On Sun, Mar 12, 2017 at 3:42 PM, Augie Fackler <raf at durin42.com> wrote:
> # HG changeset patch
> # User Augie Fackler <augie at google.com>
> # Date 1489304265 14400
> #      Sun Mar 12 03:37:45 2017 -0400
> # Node ID 2cd4d7ea0b19c4d5c55ccf8026ff1d7aa493a8cb
> # Parent  a8f3bbc6259aebdeeef9f58309800f4070081214
> tests: make a variable for hg binary location in test-check-py3-commands
> 
> The number of which calls in here is starting to get silly.
> 
> This is strictly better. But we may want to just introduce a $PY3HG environment variable from run-tests.py. As long as it isn't quoted, shell expansion should "just work." Or if shell expansion is a problem, we can install a py3hg wrapper script that sets python3 in the shebang and alias that to $PY3HG or something.

I'm hoping we can get a whole .t file that passes in Python 3 soon, and this can be obsoleted by a buildbot target that does python3  run-tests.py with a python3 hg.