outer join simplification should be applied in normalization phase

## Enhancement
```
drop table if exists t;
create table t(a int primary key, b int);
insert into t values (1, 11), (4, 44), (2, 22), (3, 33);
set session tidb_executor_concurrency = 4;
set @@session.tidb_hash_join_concurrency = 5;
set @@session.tidb_distsql_scan_concurrency = 15;

mysql> explain select max(a.a) from t a left join t b on a.a = b.a;
+----------------------------------+---------+-----------+---------------+-------------------------------------------------------------------------------------------------------------------------------------+
| id | estRows | task | access object | operator info |
+----------------------------------+---------+-----------+---------------+-------------------------------------------------------------------------------------------------------------------------------------+
| StreamAgg_14 | 1.00 | root | | funcs:max(test.t.a)->Column#5 |
| └─IndexJoin_70 | 1.25 | root | | left outer join, inner:TableReader_67, left side:TopN_52, outer key:test.t.a, inner key:test.t.a, equal cond:eq(test.t.a, test.t.a) |
| ├─TopN_52(Build) | 1.00 | root | | test.t.a:desc, offset:0, count:1 |
| │ └─TableReader_58 | 1.00 | root | | data:TopN_57 |
| │ └─TopN_57 | 1.00 | cop[tikv] | | test.t.a:desc, offset:0, count:1 |
| │ └─TableFullScan_34 | 4.00 | cop[tikv] | table:a | keep order:false, stats:pseudo |
| └─TableReader_67(Probe) | 1.00 | root | | data:TableRangeScan_66 |
| └─TableRangeScan_66 | 1.00 | cop[tikv] | table:b | range: decided by [test.t.a], keep order:false, stats:pseudo |
+----------------------------------+---------+-----------+---------------+-------------------------------------------------------------------------------------------------------------------------------------+
8 rows in set (0.01 sec)

```

currently we saw old-default-off transformation rule `EliminateOuterJoinBelowAggregation` could simplify this query to the plan as below
```
HashAgg_36 1.00 root funcs:max(planner__cascades__integration.t.a)->Column#5
└─Limit_38 1.00 root offset:0, count:1
└─TableReader_43 1.00 root data:Limit_44
└─Limit_44 1.00 cop[tikv] offset:0, count:1
└─TableFullScan_42 1.00 cop[tikv] table:a keep order:true, desc, stats:pseudo
```
since this is a `always-good-rule` and it's valuable as above, we should migrate it to normalization phase, or current logical optimization phase, to make it public.