[indic-like] Add per-lookup per-syllable flag

This allows mix-and-matching per-syllable and other lookups.
In fact, removes the clear-syllables call completely.

Fixes https://github.com/harfbuzz/harfbuzz/issues/3513

src/hb-ot-map.cc

diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 12ceea5..f085c78 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -117,7 +117,8 @@
 				  hb_mask_t     mask,
 				  bool          auto_zwnj,
 				  bool          auto_zwj,
-				  bool          random)
+				  bool          random,
+				  bool          per_syllable)
 {
   unsigned int lookup_indices[32];
   unsigned int offset, len;
@@ -145,6 +146,7 @@
       lookup->auto_zwnj = auto_zwnj;
       lookup->auto_zwj = auto_zwj;
       lookup->random = random;
+      lookup->per_syllable = per_syllable;
     }
 
     offset += len;
@@ -277,6 +279,7 @@
     map->auto_zwnj = !(info->flags & F_MANUAL_ZWNJ);
     map->auto_zwj = !(info->flags & F_MANUAL_ZWJ);
     map->random = !!(info->flags & F_RANDOM);
+    map->per_syllable = !!(info->flags & F_PER_SYLLABLE);
     if ((info->flags & F_GLOBAL) && info->max_value == 1) {
       /* Uses the global bit */
       map->shift = global_bit_shift;
@@ -319,7 +322,8 @@
 		       m.features[i].mask,
 		       m.features[i].auto_zwnj,
 		       m.features[i].auto_zwj,
-		       m.features[i].random);
+		       m.features[i].random,
+		       m.features[i].per_syllable);
 
       /* Sort lookups and merge duplicates */
       if (last_num_lookups < m.lookups[table_index].length)