[Indic] Improve check on ligatures

Only skip actual ligatures, not marks in-between ligature components.

src/hb-ot-layout-gsubgpos-private.hh

@@ -51,6 +51,11 @@ get_lig_comp (const hb_glyph_info_t &info)
 {
   return info.lig_props() & 0x0F;
 }
+static inline bool
+is_a_ligature (const hb_glyph_info_t &info)
+{
+  return unlikely (get_lig_id (info) && ~get_lig_comp (info));
+}
 
 static inline uint8_t allocate_lig_id (hb_buffer_t *buffer) {
   uint8_t lig_id = buffer->next_serial () & 0x0F;

src/hb-ot-shape-complex-indic.cc

@@ -201,7 +201,7 @@ static inline bool
 is_one_of (const hb_glyph_info_t &info, unsigned int flags)
 {
   /* If it ligated, all bets are off. */
-  if (unlikely (get_lig_id (info))) return false;
+  if (is_a_ligature (info)) return false;
   return !!(FLAG (info.indic_category()) & flags);
 }