Another failing integration test

[itamarst]

Only happens on CircleCI. Example: ​https://app.circleci.com/pipelines/github/tahoe-lafs/tahoe-lafs/4569/workflows/b4f5b382-887c-46b0-9b33-75379e796970/jobs/80350

...
alice: 2023-05-09T15:10:55+0000 [-] Failed to connect to a HTTP storage server: An error occurred while connecting: 99: Cannot assign requested address.
alice: 2023-05-09T15:10:55+0000 [-] Failed to connect to a HTTP storage server: An error occurred while connecting: 99: Cannot assign requested address.
alice: 2023-05-09T15:10:55+0000 [-] Failed to connect to a HTTP storage server: An error occurred while connecting: 99: Cannot assign requested address.
alice: 2023-05-09T15:10:55+0000 [-] Failed to connect to a HTTP storage server: An error occurred while connecting: 99: Cannot assign requested address.
alice: 2023-05-09T15:10:55+0000 [-] Failed to connect to a HTTP storage server: An error occurred while connecting: 99: Cannot assign requested address.
alice: 2023-05-09T15:10:55+0000 [twisted.web.client._HTTP11ClientFactory#info] Starting factory _HTTP11ClientFactory(<function HTTPConnectionPool._newConnection.<locals>.quiescentCallback at 0x7f9d03146c10>, <twisted.internet.endpoints._WrapperEndpoint object at 0x7f9d01e6bbb0>)
alice: 2023-05-09T15:10:55+0000 [twisted.web.client._HTTP11ClientFactory#info] Stopping factory _HTTP11ClientFactory(<function HTTPConnectionPool._newConnection.<locals>.quiescentCallback at 0x7f9d03146c10>, <twisted.internet.endpoints._WrapperEndpoint object at 0x7f9d01e6bbb0>)
alice: 2023-05-09T15:10:55+0000 [twisted.web.client._HTTP11ClientFactory#info] Starting factory _HTTP11ClientFactory(<function HTTPConnectionPool._newConnection.<locals>.quiescentCallback at 0x7f9d01ebbd30>, <twisted.internet.endpoints._WrapperEndpoint object at 0x7f9d028bc4c0>)
alice: 2023-05-09T15:10:55+0000 [twisted.web.client._HTTP11ClientFactory#info] Stopping factory _HTTP11ClientFactory(<function HTTPConnectionPool._newConnection.<locals>.quiescentCallback at 0x7f9d01ebbd30>, <twisted.internet.endpoints._WrapperEndpoint object at 0x7f9d028bc4c0>)
...
ERROR integration/test_web.py::test_mkdir_with_children - twisted.internet.defer.TimeoutError: (120, 'Deferred')

[itamarst]

Seems to be a shutdown issue with alice, probably. Possibly the http connection pool should be more explicitly shut down.

[GitHub <noreply@…>]

In 41131ca/trunk:

Merge pull request #1302 from tahoe-lafs/4028-more-integration

Fix another integration test failure

Fixes ticket:4028