Fixed results for NULL and NaN distances [skip ci]

test/expected/hnsw_cosine.out

@@ -11,9 +11,20 @@ SELECT * FROM t ORDER BY val <=> '[3,3,3]';
  [1,2,4]
 (3 rows)
 
+SELECT * FROM t ORDER BY val <=> '[0,0,0]';
+   val   
+---------
+ [1,1,1]
+ [1,2,4]
+ [1,2,3]
+(3 rows)
+
 SELECT * FROM t ORDER BY val <=> (SELECT NULL::vector);
- val 
------
-(0 rows)
+   val   
+---------
+ [1,1,1]
+ [1,2,4]
+ [1,2,3]
+(3 rows)
 
 DROP TABLE t;