Fix testcases from the previous push: add missing DROP TABLE statement

mysql-test/r/subselect_sj2.result

@@ -821,5 +821,6 @@ f3	f4	f4
 x	x	g
 x	x	g
 set optimizer_switch= @tmp_869012;
+DROP TABLE t1,t2,t3;
 # This must be the last in the file:
 set optimizer_switch=@subselect_sj2_tmp;

mysql-test/r/subselect_sj2_jcl6.result

@@ -832,6 +832,7 @@ f3	f4	f4
 x	x	g
 x	x	g
 set optimizer_switch= @tmp_869012;
+DROP TABLE t1,t2,t3;
 # This must be the last in the file:
 set optimizer_switch=@subselect_sj2_tmp;
 set join_cache_level=default;

mysql-test/t/subselect_sj2.test

@@ -1006,7 +1006,7 @@ WHERE ( t1.f4 ) IN ( SELECT f4 FROM t3 )
 AND t2.f4 != t1.f3 ;
 set optimizer_switch= @tmp_869012;
 
-
+DROP TABLE t1,t2,t3;
 
 --echo # This must be the last in the file:
 set optimizer_switch=@subselect_sj2_tmp;