Improved test [skip ci]

Author: ankane

test/expected/hnsw_vector.out

@@ -190,4 +190,6 @@ SHOW hnsw.scan_mem_multiplier;
 
 SET hnsw.scan_mem_multiplier = 0;
 ERROR:  0 is outside the valid range for parameter "hnsw.scan_mem_multiplier" (1 .. 1000)
+SET hnsw.scan_mem_multiplier = 1001;
+ERROR:  1001 is outside the valid range for parameter "hnsw.scan_mem_multiplier" (1 .. 1000)
 DROP TABLE t;

test/sql/hnsw_vector.sql

@@ -109,5 +109,6 @@ SET hnsw.max_scan_tuples = 0;
 SHOW hnsw.scan_mem_multiplier;
 
 SET hnsw.scan_mem_multiplier = 0;
+SET hnsw.scan_mem_multiplier = 1001;
 
 DROP TABLE t;