tests: stop skipping `mercurial/pure/osutil.py` during pytype runs

Not sure when the original issue(s) were fixed, but it works for me now.

contrib/check-pytype.sh

@@ -56,7 +56,6 b' cd "$(hg root)"'
 # mercurial/localrepo.py        # [attribute-error]
 # mercurial/manifest.py         # [unsupported-operands], [wrong-arg-types]
 # mercurial/minirst.py          # [unsupported-operands], [attribute-error]
-# mercurial/pure/osutil.py      # [invalid-typevar], [not-callable]
 # mercurial/pure/parsers.py     # [attribute-error]
 # mercurial/repoview.py         # [attribute-error]
 # mercurial/testing/storage.py  # tons of [attribute-error]
@@ -116,7 +115,6 b' pytype --keep-going --jobs auto \\'
     -x mercurial/localrepo.py \
     -x mercurial/manifest.py \
     -x mercurial/minirst.py \
-    -x mercurial/pure/osutil.py \
     -x mercurial/pure/parsers.py \
     -x mercurial/repoview.py \
     -x mercurial/testing/storage.py \