fix innodb.innodb_uninstall test to cleanup after itself

It caused the following main.innodb_load_xa to fail.

mysql-test/suite/innodb/r/innodb_uninstall.result

@@ -11,10 +11,10 @@ sleep(1)
 0
 Warnings:
 Warning	1620	Plugin is busy and will be uninstalled on shutdown
-drop table t1;
 install plugin innodb soname 'ha_innodb';
 Warnings:
 Warning	1105	Cannot enable tc-log at run-time. XA features of InnoDB are disabled
+drop table t1;
 create table t2(a int not null primary key) engine=innodb;
 insert into t2 values(1);
 drop table t2;

mysql-test/suite/innodb/t/innodb_uninstall.test

@@ -30,8 +30,6 @@ reap;
 
 --source include/restart_mysqld.inc
 
-drop table t1;
-
 #
 # Another test that caused hang.
 #
@@ -39,6 +37,8 @@ drop table t1;
 connect (con1, localhost, root);
 connection con1;
 install plugin innodb soname 'ha_innodb';
+
+drop table t1;
 create table t2(a int not null primary key) engine=innodb;
 insert into t2 values(1);
 drop table t2;