[PATCH 2 of 2 pypy-support] tests: use $PYTHON instead of hardcoding python

[Augie Fackler]

On Thu, Oct 16, 2014 at 3:37 PM, Matt Mackall <mpm at selenic.com> wrote:
> Two problems here:
>
> - no check-code rule to prevent back-creep
> - almost all of this should be switched to ">>>" anyway

I'll follow up with a check-code rule shortly.