test-check-code: do not use xargs
We have too many files, and passing them via arguments could cause strange
errors on some platforms [1]. Since check-code.py can now take "-" and read
file names from stdin, use it instead of xargs to avoid the argv size limit.
[1]: https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-April/096346.html
#require test-repo
$ . "$TESTDIR/helpers-testrepo.sh"
$ cd "`dirname "$TESTDIR"`"
look for python scripts that do not use /usr/bin/env
$ hg files 'set:grep(r"^#!.*?python") and not grep(r"^#!/usr/bi{1}n/env python")'
[1]
look for shell scripts that do not use /bin/sh
$ hg files 'set:grep(r"^#!.*/bi{1}n/sh") and not grep(r"^#!/bi{1}n/sh")'
[1]