CI timeout due to bootstrap is very slow

[lance6716]

https://do.pingcap.net/jenkins/blue/organizations/jenkins/pingcap%2Ftidb%2Fghpr_unit_test/detail/ghpr_unit_test/20093/pipeline

PASS: TestReadPartitionTable (71.84s)

And if we dig into which stage this test is stuck at, we will see

[2023/03/21 15:34:51.514 +08:00] [INFO] [session.go:3813] ["CRUCIAL OPERATION"] [conn=0] [schemaVersion=0] [cur_db=mysql] [sql="CREATE DATABASE IF NOT EXISTS test"] [user=]
...
[2023/03/21 15:35:53.456 +08:00] [INFO] [session.go:3813] ["CRUCIAL OPERATION"] [conn=0] [schemaVersion=43] [cur_db=mysql] [sql="CREATE TABLE IF NOT EXISTS mysql.load_data_jobs (\n       job_id bigint(64) NOT NULL AUTO_INCREMENT,\n       expected_status ENUM('running', 'paused', 'canceled') NOT NULL DEFAULT 'running',\n       create_time TIMESTAMP(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6),\n       start_time TIMESTAMP(6) NULL DEFAULT NULL,\n       update_time TIMESTAMP(6) NULL DEFAULT NULL,\n       end_time TIMESTAMP(6) NULL DEFAULT NULL,\n       data_source TEXT NOT NULL,\n       table_schema VARCHAR(64) NOT NULL,\n       table_name VARCHAR(64) NOT NULL,\n       import_mode VARCHAR(64) NOT NULL,\n       create_user VARCHAR(32) NOT NULL,\n       progress TEXT DEFAULT NULL,\n       result_message TEXT DEFAULT NULL,\n       error_message TEXT DEFAULT NULL,\n       PRIMARY KEY (job_id),\n       KEY (create_time),\n       KEY (create_user));"] [user=]

bootstrap costs 62s in 71.84s