Summary: The prior diff d21912a64f0130370dd3e673032731c5fa308bf4 was changed enough that it no longer fixed PgConnTest.SessionExpiration with table locking enabled.

Test Plan:
cherry pick this diff onto arcpatch-D44416 and run:
```
./yb_build.sh release --cxx-test pgwrapper_pg_conn-test --cxx-test-filter-re pg_conn-test --gtest_filter PgConnTest.SessionExpiration
```

Reviewers: bkolagani

Reviewed By: bkolagani

Subscribers: yql, ybase, rthallam

Differential Revision: https://phorge.dev.yugabyte.com/D47846