Fix net_unittests failure caused by assuming "foo" would never be a valid TLD

Charleston Road Registry applied for, and was granted, "foo" as a TLD on
2014-01-30

BUG=37436
R=dmichael@chromium.org
TBR=pkasting

Review URL: https://codereview.chromium.org/194703014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256341 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256341