test_regressions is failing on .NET Core

[slozier]

test_cp24692 in test_regressions is failing on .NET Core. I noticed it failing when testing 2.1 Preview but what I tried with 2.0 it's also failing (but it doesn't on AppVeyor?).

It appears that an OSError is thrown instead of the expected WindowsError:

OSError: [Errno -2146232800] Access to the path '\?\C:\IronPython.2.7.8\netcoreapp2.0\cp24692_testdir' is denied.