bpo-35411: Skip test_urllib2net FTP tests on Travis CI (GH-10907)


On Travis CI, FTP tests of test_urllib2net randomly fail with "425
Security: Bad IP connecting".

test.pythoninfo now also logs TRAVIS environment variable.
(cherry picked from commit c11b3b19a5b022c6c229043d37f9a9fd06f22500)

Co-authored-by: Victor Stinner <vstinner@redhat.com>
diff --git a/Lib/test/pythoninfo.py b/Lib/test/pythoninfo.py
index 30e6f21..9befd12 100644
--- a/Lib/test/pythoninfo.py
+++ b/Lib/test/pythoninfo.py
@@ -256,6 +256,7 @@
         "TIX_LIBRARY",
         "TMP",
         "TMPDIR",
+        "TRAVIS",
         "TZ",
         "USERPROFILE",
         "VIRTUAL_ENV",