planner: fix union scan on partition table bug

[crazycs520]

What problem does this PR solve?

fix union scan on partition table bug

create table t (a int) partition by hash(a) partitions 4;
begin
insert into t values (0),(1);
select * from t where a>0; 
+---+
| a |
+---+
| 1 |
| 0 | --bug: filter is a>0
+---+

What is changed and how it works?

Check List

Tests

• Unit test

Code changes

• Has exported function/method change

Side effects

Related changes

• Need to cherry-pick to the release branch

[crazycs520]

/run-all-tests

[crazycs520]

@tiancaiamao @zz-jason PTAL

[codecov]

Codecov Report

Merging #11187 into master will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff             @@
##             master     #11187   +/-   ##
===========================================
  Coverage   82.1848%   82.1848%           
===========================================
  Files           423        423           
  Lines         94678      94678           
===========================================
  Hits          77811      77811           
  Misses        11553      11553           
  Partials       5314       5314

[eurekaka]

LGTM

[alivxxx]

LGTM