mysql: replace t.Fatalf and t.Errorf with require and assert, add more specific error checks
mysql: replace t.Fatalf and t.Errorf with require and assert, add more specific error checks

Signed-off-by: deepthi <3f83f38ad2e2ddcc47e21eb12a05ce66eb4cf525@planetscale.com>

mahak/vitess,vitessio/vitess,tinyspeck/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,mahak/vitess,tinyspeck/vitess,tinyspeck/vitess,vitessio/vitess,mahak/vitess,mahak/vitess,mahak/vitess,tinyspeck/vitess,tinyspeck/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,mahak/vitess,tinyspeck/vitess,vitessio/vitess,tinyspeck/vitess