Remove duplicated tests from test-ot-tag (#1958)

diff --git a/test/api/test-ot-tag.c b/test/api/test-ot-tag.c
index d0334cd..958fd6b 100644
--- a/test/api/test-ot-tag.c
+++ b/test/api/test-ot-tag.c
@@ -351,9 +351,6 @@
   test_tag_from_language ("ZHH", "yue-Hant");
   test_tag_from_language ("ZHS", "yue-Hans");
 
-  test_tag_from_language ("ZHS", "zh"); /* Chinese */
-  test_tag_from_language ("ZHS", "zh-xx");
-
   test_language_two_way ("ABC", "abc");
   test_language_two_way ("ABCD", "x-hbotabcd");
   test_tag_from_language ("ABC", "asdf-asdf-wer-x-hbotabc-zxc");