Mysql test runner Crashing while using set session transaction

[Alkaagr81]

REPEATABLE READ is supported by tidb but test runner is no allowing.
same SET @@autocommit=0; this is also not working .

connect (con1,localhost,root,,test);
connection default;
SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ;
CREATE TABLE t1 (s1 INT) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1),(2);
COMMIT;

Output is

skip building tidb-server, using existing binary: /Users/sachinagrawal/.tiup/components/tidb/v5.2.1/tidb-server
building mysql-test binary: ./mysql_test
build mysql_test successfully
start tidb-server, log file: ./mysql-test.out
tidb-server(PID: 69322) started
record result for case: "crashing"
INFO[0000] recording tests: [crashing]                  
WARN[0000] Create new db&{0 {root:@tcp(127.0.0.1:4001)/test?strict=true&time_zone=%27Asia%2FShanghai%27 0x1c56d40} 0 {0 0} [0xc0000aa870] map[] 0 1 0xc00008c120 false map[0xc0000aa870:map[0xc0000aa870:true]] map[] 0 0 0 0 <nil> 0 0 0 0 0x109b340} 
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x70 pc=0x10e27a6]

goroutine 7 [running]:
database/sql.(*Tx).Commit(0x0, 0x14eac00, 0x1)
	/usr/local/go/src/database/sql/sql.go:2151 +0x26
main.(*tester).commit(...)
	/Users/sachinagrawal/go/pkg/mod/github.com/pingcap/mysql-tester@v0.0.0-20211026071309-3ee4da8b351d/src/main.go:673
main.(*tester).stmtExecute(0xc0000aa750, 0xc00002aa94, 0x6, 0xc00002aa94, 0x7, 0x3, 0x2, 0x14fa6c8, 0xc0001320a0, 0x1, ...)
	/Users/sachinagrawal/go/pkg/mod/github.com/pingcap/mysql-tester@v0.0.0-20211026071309-3ee4da8b351d/src/main.go:566 +0xb6
main.(*tester).execute(0xc0000aa750, 0xc00002aa94, 0x6, 0xc00002aa94, 0x7, 0x3, 0x2, 0x0, 0x0)
	/Users/sachinagrawal/go/pkg/mod/github.com/pingcap/mysql-tester@v0.0.0-20211026071309-3ee4da8b351d/src/main.go:621 +0x13d
main.(*tester).Run(0xc0000aa750, 0x0, 0x0)
	/Users/sachinagrawal/go/pkg/mod/github.com/pingcap/mysql-tester@v0.0.0-20211026071309-3ee4da8b351d/src/main.go:307 +0x666
main.testBatch.Run(0xc00000c1e0, 0x1, 0x1e)
	/Users/sachinagrawal/go/pkg/mod/github.com/pingcap/mysql-tester@v0.0.0-20211026071309-3ee4da8b351d/src/main.go:928 +0xb3
created by main.executeTests
	/Users/sachinagrawal/go/pkg/mod/github.com/pingcap/mysql-tester@v0.0.0-20211026071309-3ee4da8b351d/src/main.go:958 +0xc5