Bug 1902985 - Turn on test_osPreferences.js on GeckoView. r=platform-i18n-reviewers,dminor

Although I turned off this since mobile didn't support ICU and xpcshell
didn't run on Java service. But now, we can run this test even if
GeckoView.

Differential Revision: https://phabricator.services.mozilla.com/D213919

intl/locale/tests/unit/xpcshell.toml

@@ -18,4 +18,3 @@ skip-if = ["os == 'android'"] # bug 1309447
 ["test_localeService_negotiateLanguages.js"]
 
 ["test_osPreferences.js"]
-skip-if = ["os == 'android'"] # bug 1344596