tidb parser dependency is at old location

[morgo]

The parser used by the mysql tester is from github.com/pingcap/parser not github.com/pingcap/tidb/parser.

This is a problem because some of the tests require newer features:

FATA[0000] run test [ctype_gbk] err: sql:SET NAMES gbk;: [parser:1064]You have an error in your SQL syntax; check the manual that corresponds to your TiDB version for the right syntax to use [parser:1115]Unknown character set: 'gbk' 

[morgo]

When I tried to bump this location, it forced a newer version of the MySQL driver:

$ go get github.com/pingcap/tidb/parser@master
go get: upgraded github.com/go-sql-driver/mysql v1.3.0 => v1.6.0
go get: added github.com/pingcap/tidb/parser v0.0.0-20211111185706-64f34345d982

I have filed this separately at https://github.com/pingcap/mysql-tester/issues/25