Don't collect regrtest_data

[felixonmars]

Steps

• Add yourself to CONTRIBUTORS if you are a new contributor.
• Add a ChangeLog entry describing what your PR does.
• If it's a new feature or an important bug fix, add a What's New entry in doc/whatsnew/<current release.rst>.
• Write a good description on what the PR does.

Description

This fixes the current test failures in master:

============================= test session starts ==============================
platform linux -- Python 3.8.0, pytest-5.2.3, py-1.8.0, pluggy-0.13.0
rootdir: /build/python-pylint/src/pylint-pylint-2.4.4, inifile: pytest.ini
collected 1338 items / 2 errors / 201 deselected / 1135 selected

==================================== ERRORS ====================================
_________ ERROR collecting tests/regrtest_data/bad_package/__init__.py _________
/usr/lib/python3.8/site-packages/_pytest/python.py:512: in _importtestmodule
    mod = self.fspath.pyimport(ensuresyspath=importmode)
/usr/lib/python3.8/site-packages/py/_path/local.py:701: in pyimport
    __import__(modname)
E     File "/build/python-pylint/src/pylint-pylint-2.4.4/tests/regrtest_data/bad_package/__init__.py", line 2
E       raise missing.Missing..
E                             ^
E   SyntaxError: invalid syntax
_________ ERROR collecting tests/regrtest_data/beyond_top/__init__.py __________
tests/regrtest_data/beyond_top/__init__.py:1: in <module>
    from ... import Something
E   ValueError: attempted relative import beyond top-level package
!!!!!!!!!!!!!!!!!!! Interrupted: 2 errors during collection !!!!!!!!!!!!!!!!!!!!
======================= 201 deselected, 2 error in 1.77s =======================

Type of Changes

	Type
✓	🐛 Bug fix

[ngie-eign]

This definitely addresses some of the issues I was seeing yesterday, but not all of the issues. Unfortunately one of the tests still fails on master in all environments (it looks like one or more of the APIs changed).

[PCManticore]

Thanks for the PR @felixonmars I left a comment on the similar PR from astroid: pylint-dev/astroid#723 (comment) Not sure how to reproduce these errors you are getting.

[felixonmars]

I ran a plain pytest command in the source tree. I remember seeing this in master too but I cannot reproduce now. Perhaps it was a temporary error with pytest 5.2.2 or 5.2.3 but now fixed in 5.2.4.

[felixonmars]

UPDATE: It was pytest-dev/pytest#6194