tests/list-tree.py

run-tests: stop ignoring venv-installed packages

This will allow test dependencies to be installed within a venv, instead of
tampering with sys/user sites.  One thing to note here is that the `VIRTUAL_ENV`
path takes precedence over system-site, unlike when run directly with an
activated `venv`.  For example, `sys.path` as viewed from a feature test in
`hghave.py`, when running `hghave vcr` directly with an activated `venv`:

    sys.path: [
        '/home/jenkins/hg-committed/tests',
        '/usr/lib/python38.zip',
        '/usr/lib/python3.8',
        '/usr/lib/python3.8/lib-dynload',
        '/home/jenkins/test_venv/lib/python3.8/site-packages'
    ]

vs `sys.path` from the same feature test, when run by `run-tests.py` with this
change:

    sys.path: [
        '/home/jenkins/hg-committed/tests',
        '/home/jenkins/hg-committed',
        '/home/jenkins/hg-committed/tests',
        '/home/jenkins/test_venv/lib/python3.8/site-packages',
        '/usr/lib/python38.zip',
        '/usr/lib/python3.8',
        '/usr/lib/python3.8/lib-dynload',
        '/home/jenkins/.local/lib/python3.8/site-packages',
        '/usr/local/lib/python3.8/dist-packages',
        '/usr/lib/python3/dist-packages'
    ]

import argparse
import os

ap = argparse.ArgumentParser()
ap.add_argument('path', nargs='+')
opts = ap.parse_args()


def gather():
    for p in opts.path:
        if not os.path.exists(p):
            return
        if os.path.isdir(p):
            yield p + os.path.sep
            for dirpath, dirs, files in os.walk(p):
                for d in dirs:
                    yield os.path.join(dirpath, d) + os.path.sep
                for f in files:
                    yield os.path.join(dirpath, f)
        else:
            yield p


print('\n'.join(sorted(gather(), key=lambda x: x.replace(os.path.sep, '/'))))