test: remove case

tests/script/tsim/sma/drop_sma.sim

@@ -50,6 +50,13 @@ sql create table if not exists stb (ts timestamp, c1 int, c2 float, c3 double) t
 print --> create sma
 sql create sma index sma_index_name1 on stb function(max(c1),max(c2),min(c1)) interval(6m,10s) sliding(6m);
 
+print --> show indexes
+sql show d1.indexes
+if $rows != 1 then 
+  return -1
+endi
+
+return 
 print --> drop stb
 sql drop table stb;