Add "new" Myanmar OT Script tag

Windows 8 added support for Myanmar shaping using the "mym2" script tag,
even though Windows never supported the old "mymr" tag.

src/hb-ot-tag.cc

@@ -93,6 +93,7 @@ hb_ot_new_tag_from_script (hb_script_t script)
     case HB_SCRIPT_ORIYA:		return HB_TAG('o','r','y','2');
     case HB_SCRIPT_TAMIL:		return HB_TAG('t','m','l','2');
     case HB_SCRIPT_TELUGU:		return HB_TAG('t','e','l','2');
+    case HB_SCRIPT_MYANMAR:		return HB_TAG('m','y','m','2');
   }
 
   return HB_OT_TAG_DEFAULT_SCRIPT;
@@ -111,6 +112,7 @@ hb_ot_new_tag_to_script (hb_tag_t tag)
     case HB_TAG('o','r','y','2'):	return HB_SCRIPT_ORIYA;
     case HB_TAG('t','m','l','2'):	return HB_SCRIPT_TAMIL;
     case HB_TAG('t','e','l','2'):	return HB_SCRIPT_TELUGU;
+    case HB_TAG('m','y','m','2'):	return HB_SCRIPT_MYANMAR;
   }
 
   return HB_SCRIPT_UNKNOWN;

test/api/test-ot-tag.c

@@ -132,6 +132,7 @@ test_ot_tag_script_indic (void)
   test_indic_tags ("ory2", "orya", HB_SCRIPT_ORIYA);
   test_indic_tags ("tml2", "taml", HB_SCRIPT_TAMIL);
   test_indic_tags ("tel2", "telu", HB_SCRIPT_TELUGU);
+  test_indic_tags ("mym2", "mymr", HB_SCRIPT_MYANMAR);
 }