Resolves: #856320
    
    - Improve check whether a phrase is simplified or traditional Chinese
      The improvement is to ignore all non-Han characters when
      doing the check.
      This is to avoid classifying a simplified Chinese string as
      traditional just because it happens to include some non-Chinese
      characters, for example box drawing characters, which cannot be
      converted to gb2312 but happen to be convertible to big5hkscs.
      This fixes the problem in the emoji-table input method that most
      phrases cannot be input at all.