Skip test_nanny_worker_port_range

[mrocklin]

We test this functionality in test_nanny.py and test_worker.py.
We also test the worker --worker-port keyword in the test just above.
I don't know why this fails sometimes, I suspect due to some flakiness
with the popen context manager. This is fringe enough and pops up often
enough that I'm fine just skipping

• Closes #xxxx
• Tests added / passed
• Passes pre-commit run --all-files

[mrocklin]

Merging later tomorrow if there are no comments

[github-actions]

Unit Test Results

       18 files  +       4         18 suites  +4   9h 49m 46s ⏱️ + 1h 49m 11s
  2 703 tests ±       0    2 616 ✔️  -        1       83 💤 ±    0  4 ❌ +1 
24 163 runs  +5 354  22 861 ✔️ +5 058  1 298 💤 +295  4 ❌ +1 

For more details on these failures, see this check.

Results for commit 5435641. ± Comparison against base commit 8906cab.

[mrocklin]

I tried running the distributed/cli test suite in a loop 50 times locally and couldn't reproduce the original issue. I'd like to figure out what's actuallly going on here.