More conservative interpretation of PathFinder.find_spec() failures

[jacobtylerwalls]

Steps

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Description

First of all, there was just an issue in pytest to work around. See pytest-dev/apipkg#13.

Second, I think it was wrong to assume that any ValueError from importlib signified a namespace package. I was originally just trying to pass the astroid test case that promises support for the very old pkg_resources namespace package protocol, i.e. .pth files. When .pth files are executed, they're in sys.modules, so here I just check for that.

Type of Changes

	Type
✓	🐛 Bug fix

Related Issue

Follow up to #1536. Resolves issue in pandas revealed by pylint primer.

[coveralls]

Pull Request Test Coverage Report for Build 2416557299

• 8 of 8 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.006%) to 91.933%

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Totals
Change from base Build 2413685707:	0.006%
Covered Lines:	9254
Relevant Lines:	10066

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💛 - Coveralls

[DanielNoord]

Should we add some tests for this/