executor: fix processlist's Mem is not zero when HashJoin finished

[wshwsh12]

What problem does this PR solve?

Issue Number: close #34571

Problem Summary:
This pr #33918 have tracked more memory usage, but forgot to clear the memory usage when sql is finished.

What is changed and how it works?

Check List

Tests

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

conn-1:
        drop table if exists t;
        create table t (a int);
        drop table if exists ta;
        create table ta (b int);
        insert into t values (1);
        insert into ta values (11);
        drop table if exists session_info;
        create table session_info(id int, connection_id int);
        insert into session_info values (1, 1);
        select * from t, ta;

conn-2:
        select * from information_schema.processlist where command='Sleep';

• 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.

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• XuHuaiyu
• guo-shaoge

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[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/26e67e3cc3bb313f30b25d9a61357add6013fa48

[hawkingrei]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 7828acd

[sre-bot]

TiDB MergeCI notify

🔴 Bad News! New failing [1] after this pr merged.
These new failed integration tests seem to be caused by the current PR, please try to fix these new failed integration tests, thanks!

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci/integration-cdc-test	🟥 failed 1, success 33, total 34	34 min	New failing
idc-jenkins-ci-tidb/integration-common-test	🟢 all 11 tests passed	12 min	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	9 min 17 sec	Existing passed
idc-jenkins-ci-tidb/integration-ddl-test	🟢 all 6 tests passed	6 min 39 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	6 min 39 sec	Existing passed
idc-jenkins-ci-tidb/common-test	🟢 all 12 tests passed	6 min 32 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	5 min 29 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	5 min 19 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	4 min 28 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed