planner: fix column pruner will clear handleCols and lead filling _tidb_rowid when datasource's schema length is 0 for a pkIsHandled table (#45217)

[ti-chi-bot]

This is an automated cherry-pick of #45217

What problem does this PR solve?

Issue Number: close #44579

Problem Summary:

What is changed and how it works?

step1: when column pruner #1 steps into datasource, it will keep column ‘a’ and clear handleCols in the case below
step2: ppd logical optimization will clear invalid condition count(a) = null, which is always false

step3: as is known to all, the last column pruner finds there is nothing required by datasource parent, it will clear all the schema columns existed now, and try to add a handle col (which cleared in step 1), therefore it adds a _tidb_rowid instead for a clustered table.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

tiup playground v7.2.0 --tiflash=1 --db.binpath="/Users/arenatlx/go/src/github.com/pingcap/tidb/bin/tidb-server"
create table if not exists test.t1(a int(11) DEFAULT NULL, id int(11) NOT NULL, PRIMARY KEY (`id`) /*T![clustered_index] CLUSTERED */);
alter table test.t1 set tiflash replica 1;
use test; set tidb_enforce_mpp=on; set tidb_isolation_read_engines='tiflash';
explain select sum(1) as c from test.t1 having count(*)>1 or count(a)= null;
select sum(1) as c from test.t1 having count(*)>1 or count(a)= null;

• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

planner: fix column pruner will clear handleCols and leading filling _tidb_rowid for a pkIsHanle table

[elsa0520]

LGTM

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-07-10 07:04:29.181723982 +0000 UTC m=+315560.952062695: ☑️ agreed by hawkingrei.
• 2023-07-10 07:10:47.863674231 +0000 UTC m=+315939.634012944: ☑️ agreed by elsa0520.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chrysan, elsa0520, hawkingrei

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