TiDB should support equivalence class propagation for JOIN op

## Bug Report

Please answer these questions before submitting your issue. Thanks!

### 1. Minimal reproduce step (Required)

有四个表：

```
CREATE TABLE p0 (
tenant_id bigint(20) unsigned NOT NULL,
org_id bigint(20) unsigned NOT NULL,
poi_id bigint(20) unsigned NOT NULL,
spu_id bigint(20) unsigned NOT NULL,
type tinyint(4) unsigned NOT NULL,
name varchar(256) NOT NULL,
tenant_poi_id varchar(30) DEFAULT NULL,
UNIQUE KEY tenant_id(tenant_id,poi_id,spu_id,org_id),
KEY idx_tenant_poi_id (tenant_poi_id),
KEY idx_tps (tenant_id,poi_id,spu_id),
KEY idx_tpt (tenant_poi_id,type)
);

CREATE TABLE p1 (
id bigint(20) unsigned NOT NULL,
tenant_id bigint(20) unsigned NOT NULL,
org_id bigint(20) unsigned NOT NULL,
poi_id bigint(20) unsigned NOT NULL,
spu_id bigint(20) DEFAULT NULL,
sku_id bigint(20) unsigned NOT NULL,
tenant_poi_id varchar(30) DEFAULT NULL,
UNIQUE KEY tenant_id (tenant_id,id),
UNIQUE KEY unique_tenant_id_org_id_poi_id_sku_id (tenant_id,org_id,poi_id,sku_id),
KEY idx_spu_id (spu_id),
KEY idx_tenant_id_org_id_poi_id_spu_id (tenant_id,poi_id,spu_id),
KEY tentpoi_spu (tenant_poi_id,spu_id),
KEY idx_tenant_id_poi_id_sku_id (tenant_id,poi_id,sku_id)
);

CREATE TABLE p2 (
id bigint(20) NOT NULL AUTO_INCREMENT,
tenant_id bigint(20) unsigned NOT NULL,
org_id bigint(20) unsigned NOT NULL,
poi_id bigint(20) unsigned NOT NULL,
category_id bigint(20) unsigned NOT NULL,
spu_id bigint(20) unsigned NOT NULL,
tenant_poi_id varchar(30) DEFAULT NULL,
UNIQUE KEY id (id),
UNIQUE KEY idx_tenant_poi_id_spu_id (tenant_poi_id,spu_id)
);

CREATE TABLE p3 (
id bigint(20) unsigned NOT NULL,
tenant_id bigint(20) unsigned NOT NULL,
org_id bigint(20) unsigned NOT NULL,
poi_id bigint(20) unsigned NOT NULL,
category_id bigint(20) unsigned NOT NULL,
type tinyint(4) unsigned NOT NULL,
name varchar(256) NOT NULL,
tenant_poi_id varchar(30) DEFAULT NULL,
UNIQUE KEY tenant_id (tenant_id,poi_id,category_id,org_id),
KEY idx_tenant_poi_id (tenant_poi_id)
);
```

两个sql语句，差别只有黑体部分，输出结果差异是 p3 是否做了 FullIndexScan
sql1 :=
desc
SELECT
/\*+TIDB_HJ(p0,p1,p3),TIDB_INLJ(p2)\*/
p0.tenant_id,
p0.poi_id,
p0.spu_id,
p0.name AS spu_name
FROM
p0
JOIN p1 ON p0.tenant_id = p1.tenant_id
AND p0.poi_id = p1.poi_id
AND p0.spu_id = p1.spu_id
JOIN p2 ON p1.tenant_poi_id = p2.tenant_poi_id
AND p1.spu_id = p2.spu_id
LEFT JOIN p3 ON **p1.tenant_id = p3.tenant_id
AND p1.poi_id = p3.poi_id**
AND p2.category_id = p3.category_id
WHERE
p0.tenant_id IN ('10312060')
AND p0.poi_id IN ('600491386')
AND p0.spu_id IN ('2840204741')`

sql2 := "desc
SELECT
/\*+TIDB_HJ(p0,p1,p3),TIDB_INLJ(p2)\*/
p0.tenant_id,
p0.poi_id,
p0.spu_id,
p0.name AS spu_name
FROM
p0
JOIN p1 ON p0.tenant_id = p1.tenant_id
AND p0.poi_id = p1.poi_id
AND p0.spu_id = p1.spu_id
JOIN p2 ON p1.tenant_poi_id = p2.tenant_poi_id
AND p1.spu_id = p2.spu_id
LEFT JOIN p3 ON **p0.tenant_id = p3.tenant_id
AND p0.poi_id = p3.poi_id**
AND p2.category_id = p3.category_id
WHERE
p0.tenant_id IN ('10312060')
AND p0.poi_id IN ('600491386')
AND p0.spu_id IN ('2840204741');"

Join 形式是：((p0 inner join p1) inner join p2) left outer join p3
sql1中，p1的等值查询常量，没有传递给 p3，造成了 FullIndexScan

问题的原因是：逻辑优化阶段递归执行，给p3做常量传播优化时，((p0 inner join p1) inner join p2) 还没有做优化，还没有p2的等值谓词，所以关于p0的等值谓词，无法传递给p3。

### 2. What did you expect to see? (Required)
sql1没有对p3做优化

### 3. What did you see instead (Required)
sql1 也能产生sql2的优化结果

### 4. What is your TiDB version? (Required)
所有版本