Fix test_check on Windows

[bhrutledge]

Some of the tests are failing consistently; verbose pytest logging shows errors like:

>       assert capsys.readouterr().out == f"Checking {sdist}: " + (
            "FAILED due to warnings\n" if strict else "PASSED with warnings\n"
        )
E       AssertionError: assert ('Checking '\n 'C:\\Users\\runneradmin\\AppData\\Local\\Temp\\pytest-of-unknown\\pytest-\x1b[1m0\x1b[0m\\test_warns_missing_description0\\dist\\test-package-\x1b[1m0.0\x1b[0m.\x1b[1m1.\x1b[0mtar.gz: '\n 'PASSED with warnings\n') == ('Checking '\n 'C:\\Users\\runneradmin\\AppData\\Local\\Temp\\pytest-of-unknown\\pytest-0\\test_warns_missing_description0\\dist\\test-package-0.0.1.tar.gz: '\n 'PASSED with warnings\n')
E         - Checking C:\Users\runneradmin\AppData\Local\Temp\pytest-of-unknown\pytest-0\test_warns_missing_description0\dist\test-package-0.0.1.tar.gz: PASSED with warnings
E         + Checking C:\Users\runneradmin\AppData\Local\Temp\pytest-of-unknown\pytest-0\test_warns_missing_description0\dist\test-package-0.0.1.tar.gz: PASSED with warnings
E         ?                                                                           ++++ ++++                                                   ++++   ++++ ++++  ++++

I can't make sense of that, and I don't have access to a Windows machine. I might be able to set up a cloud desktop, but if someone has a Windows machine, and is able to run the tests locally to reproduce this, I'd appreciate it.

[sigmavirus24]

There seem to be extra bytes (control characters maybe?) in the captured output that aren't in the expected output