Merge branch 'upstream-Twisted' into twisted-remove-test-directories

.../Twisted/vtkTwisted/src/twisted/_threads/test/__init__.py

.../vtkTwisted/src/twisted/_threads/test/test_convenience.py

...isted/vtkTwisted/src/twisted/_threads/test/test_memory.py

...Twisted/vtkTwisted/src/twisted/_threads/test/test_team.py

...vtkTwisted/src/twisted/_threads/test/test_threadworker.py

...tkTwisted/src/twisted/application/runner/test/__init__.py

...kTwisted/src/twisted/application/runner/test/test_exit.py

...isted/src/twisted/application/runner/test/test_pidfile.py

...wisted/src/twisted/application/runner/test/test_runner.py

...isted/vtkTwisted/src/twisted/application/test/__init__.py

.../vtkTwisted/src/twisted/application/test/test_internet.py

...d/vtkTwisted/src/twisted/application/test/test_service.py

...vtkTwisted/src/twisted/application/twist/test/__init__.py

...wisted/src/twisted/application/twist/test/test_options.py

...kTwisted/src/twisted/application/twist/test/test_twist.py

...arty/Twisted/vtkTwisted/src/twisted/cred/test/__init__.py

...Twisted/vtkTwisted/src/twisted/cred/test/test_cramauth.py

...rty/Twisted/vtkTwisted/src/twisted/cred/test/test_cred.py

...isted/vtkTwisted/src/twisted/cred/test/test_digestauth.py

...isted/vtkTwisted/src/twisted/cred/test/test_simpleauth.py