Removed warning icons and use friendlier locale names

* Removed warning icons in locale list (b/26710677)
* Use getDisplayNameWithDialect() instead of getDisplayName()
  for the locale names (b/27066642)
* Set proper locale for the language labels (b/27130516)
* Fixed build warning in LocaleHelper (b/27148053)

Bug: 26710677
Bug: 27066642
Bug: 27130516
Bug: 27148053
Change-Id: I149a3675262b286c8b740d2ad5b02f4df31316ec