bpo-46178: Remove/rename redundant Travis CI code

[hugovk]

Follow on from #30257, some extra Travis CI bits and bobs to remove or rename.

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There's also a few extra places that added extra handling to catch random fails on Travis, I didn't touch those, but perhaps they could be reviewed/removed:

$ git grep -i travis...Lib/test/pythoninfo.py: # for device" on Travis CILib/test/pythoninfo.py: "TRAVIS",Lib/test/support/socket_helper.py: # with EADDRNOTAVAIL on Travis CILib/test/support/socket_helper.py: # EADDRNOTAVAIL on Travis CI.Lib/test/test_socket.py: # [bpo-33937](https://bugs.python.org/issue33937) the test randomly fails on Travis CI withLib/test/test_socket.py: # [bpo-33937](https://bugs.python.org/issue33937): catch also ENOMEM, the test randomly fails on Travis CI...

https://bugs.python.org/issue46178

[Mariatta]

Thanks

[bedevere-bot]

@Mariatta: Please replace # with GH- in the commit message next time. Thanks!