tests: use /usr/bin/env python for test-status-inprocess.py

everyone else uses it, and the next commit will add a rule for it

tests/test-status-inprocess.py

@@ -1,40 +1,40 b''
-#!/usr/bin/python
+#!/usr/bin/env python
 from __future__ import absolute_import, print_function
 from mercurial.ui import (
     ui,
 )
 from mercurial.localrepo import (
     localrepository,
 )
 from mercurial.commands import (
     add,
     commit,
     status,
 )
 
 u = ui()
 
 print('% creating repo')
 repo = localrepository(u, '.', create=True)
 
 f = open('test.py', 'w')
 try:
     f.write('foo\n')
 finally:
     f.close
 
 print('% add and commit')
 add(u, repo, 'test.py')
 commit(u, repo, message='*')
 status(u, repo, clean=True)
 
 
 print('% change')
 f = open('test.py', 'w')
 try:
     f.write('bar\n')
 finally:
     f.close()
 
 # this would return clean instead of changed before the fix
 status(u, repo, clean=True, modified=True)