Mysql-test runner gives error for Isolation level read committed but works in TIDB

[Alkaagr81]

SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
START TRANSACTION;

In Mysql test runner error

sachinagrawal@Sachins-MacBook-Pro mysql_test % ./run-tests.sh -s ~/pingcap/Github/tidb/bin/tidb-server -r crashing
skip building tidb-server, using existing binary: /Users/sachinagrawal/pingcap/Github/tidb/bin/tidb-server
building mysql-test binary: ./mysql_test
build mysql_test successfully
start tidb-server, log file: ./mysql-test.out
tidb-server(PID: 89440) started
record result for case: "crashing"
INFO[0000] recording tests: [crashing]                  
WARN[0000] Create new db&{0 0xc000010010 0 {0 0} [0xc0000aa000] map[] 0 1 0xc00009c000 false map[0xc0000aa000:map[0xc0000aa000:true]] map[] 0 0 0 0 <nil> 0 0 0 0 0x109bda0} 
FATA[0000] run test [crashing] err: sql:SET TRANSACTION ISOLATION LEVEL READ COMMITTED;: run "SET TRANSACTION ISOLATION LEVEL READ COMMITTED;" at line 1 err Error 1568: Transaction characteristics can't be changed while a transaction is in progress 
tidb-server(PID: 89440) stopped

In TIDB

mysql> SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
Query OK, 0 rows affected (0.00 sec)

mysql> START TRANSACTION;
Query OK, 0 rows affected (0.00 sec)