add mysql dialect tag to new group by test

Author: angelamayxie

enginetest/queries/order_by_group_by_queries.go

@@ -306,7 +306,8 @@ var OrderByGroupByScriptTests = []ScriptTest{
 		},
 	},
 	{
-		Name: "Group by true and 1",
+		Name:    "Group by true and 1",
+		Dialect: "mysql",
 		SetUpScript: []string{
 			"create table t0(c0 int)",
 			"insert into t0(c0) values(1),(123)",