Widen tuple counter variables from long to int64

Mistake in ab0dfc96; progress reporting would have wrapped around
for indexes created with more than 2^31 tuples.

Reported-by: Peter Geoghegan
Discussion: https://postgr.es/m/CAH2-Wz=WbNxc5ob5NJ9yqo2RMJ0q4HXDS30GVCobeCvC9A1L9A@mail.gmail.com

src/backend/access/hash/hashsort.c

@@ -118,7 +118,7 @@ void
 _h_indexbuild(HSpool *hspool, Relation heapRel)
 {
 	IndexTuple	itup;
-	long		tups_done = 0;
+	int64		tups_done = 0;
 #ifdef USE_ASSERT_CHECKING
 	uint32		hashkey = 0;
 #endif

src/backend/access/nbtree/nbtsort.c

@@ -1130,7 +1130,7 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 	int			i,
 				keysz = IndexRelationGetNumberOfKeyAttributes(wstate->index);
 	SortSupport sortKeys;
-	long		tuples_done = 0;
+	int64		tuples_done = 0;
 
 	if (merge)
 	{