Fix test cases to preserve the state that existed before the

test case was executed.

mysql-test/include/concurrent.inc:
  Drop created user.
mysql-test/r/concurrent_innodb_safelog.result:
  Update test case result.
mysql-test/r/concurrent_innodb_unsafelog.result:
  Update test case result.

mysql-test/include/concurrent.inc

@@ -637,7 +637,7 @@ drop table t1;
 --echo ** connection default
 connection default;
 drop table t1;
-
+drop user mysqltest@localhost;
 
 disconnect thread1;
 disconnect thread2;

mysql-test/r/concurrent_innodb_safelog.result

@@ -801,3 +801,4 @@ eta	tipo	c
 90	11	kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
 ** connection default
 drop table t1;
+drop user mysqltest@localhost;

mysql-test/r/concurrent_innodb_unsafelog.result

@@ -797,3 +797,4 @@ eta	tipo	c
 90	11	kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk
 ** connection default
 drop table t1;
+drop user mysqltest@localhost;