Case 5 of the module-resolution suite failed on macOS only, because /var
is a symlink to /private/var there: `mktemp -d` returns an unresolved
path while Python's os.getcwd() reports the resolved one, so the test
compared two spellings of the same directory. Resolving the temp
directory once at creation with `pwd -P` makes every path in the suite
consistent.
(from dev ca9eaa2c867a)