Remove useless argument from nbtree dedup function.

_bt_dedup_pass()'s heapRel argument hasn't been needed or used since
commit cf2acaf made deleting any existing LP_DEAD index tuples the
caller's responsibility.

Author: petergeoghegan

src/backend/access/nbtree/nbtdedup.c

@@ -55,8 +55,8 @@ static bool _bt_posting_valid(IndexTuple posting);
  * LP_DEAD bits set.
  */
 void
-_bt_dedup_pass(Relation rel, Buffer buf, Relation heapRel, IndexTuple newitem,
-			   Size newitemsz, bool bottomupdedup)
+_bt_dedup_pass(Relation rel, Buffer buf, IndexTuple newitem, Size newitemsz,
+			   bool bottomupdedup)
 {
 	OffsetNumber offnum,
 				minoff,

src/backend/access/nbtree/nbtinsert.c

@@ -2769,8 +2769,8 @@ _bt_delete_or_dedup_one_page(Relation rel, Relation heapRel,
 
 	/* Perform deduplication pass (when enabled and index-is-allequalimage) */
 	if (BTGetDeduplicateItems(rel) && itup_key->allequalimage)
-		_bt_dedup_pass(rel, buffer, heapRel, insertstate->itup,
-					   insertstate->itemsz, (indexUnchanged || uniquedup));
+		_bt_dedup_pass(rel, buffer, insertstate->itup, insertstate->itemsz,
+					   (indexUnchanged || uniquedup));
 }
 
 /*

src/include/access/nbtree.h

@@ -1157,9 +1157,8 @@ extern void _bt_parallel_advance_array_keys(IndexScanDesc scan);
 /*
  * prototypes for functions in nbtdedup.c
  */
-extern void _bt_dedup_pass(Relation rel, Buffer buf, Relation heapRel,
-						   IndexTuple newitem, Size newitemsz,
-						   bool bottomupdedup);
+extern void _bt_dedup_pass(Relation rel, Buffer buf, IndexTuple newitem,
+						   Size newitemsz, bool bottomupdedup);
 extern bool _bt_bottomupdel_pass(Relation rel, Buffer buf, Relation heapRel,
 								 Size newitemsz);
 extern void _bt_dedup_start_pending(BTDedupState state, IndexTuple base,