Do not specify language for font fallback

Providing the default locale as language when searching for
a fallback font does not improve results.

BUG=392724
R=eae,eseidel,abarth

Review URL: https://codereview.chromium.org/381893002

git-svn-id: svn://svn.chromium.org/blink/trunk@178350 bbb929c8-8fbe-4397-9dbb-9b2b20218538