Summary:
The YB_TODO had commented out an assert and said that `TestPgRegressDistinctPushdown#testPgRegressDistinctPushdown` reproduced the failure consistently. That is no longer the case. A full jenkins run shows no failures, so it seems that the underlying cause has been fixed.
Jira: DB-16886

Test Plan:
```
./yb_build.sh debug --java-test TestPgRegressDistinctPushdown#testPgRegressDistinctPushdown --sj -n 100
```

Reviewers: aagrawal

Reviewed By: aagrawal

Subscribers: yql

Differential Revision: https://phorge.dev.yugabyte.com/D44221