Investigate cleaning up of --fixture path outputs

[The-Compiler]

those look broken

Originally posted by @RonnyPfannschmidt in #8814 (comment)

[The-Compiler]

IMHO we don't strictly need this for 7.0 - the paths have always been that way, the only thing that changed is that they are now shown by default (#8626 by @rahul-kumi).

I'd like to take a quick look at if we can just display _pytest/logging.py:476 instead of ../../..$PYTHON_PREFIX/lib/python3.8/site-packages/_pytest/logging.py:476 for pytest internal stuff without too complex logic (or perhaps don't display the path at all for pytest internal fixtures).

However, if this turns out to be more complex, I'd rather leave it as-is for 7.0 and fix it in a later release.