Relax expectation of month format for en-US locale.
Relax expectation of month format for en-US locale.

The result depends on Windows version.

BUG=521036

Review URL: https://codereview.chromium.org/1288683003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@200634 bbb929c8-8fbe-4397-9dbb-9b2b20218538

Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk