Django's migrations.test_loader.LoaderTests.test_loading_order_does_not_create_circular_dependency hangs, eventually exiting with batch timestamp must be after replica GC threshold

**Describe the problem**

[A new test in Django 6.1](https://github.com/django/django/commit/e27cff68a32a0183c6b8d110b359c1c858f68cd7) hangs with CockroachDB v26.3, eventually existing with `psycopg.InternalError: batch timestamp 1784911150.526530598,0 must be after replica GC threshold 1784911162.626134007,0 (r88: /{Table/106-Max})`

**To Reproduce**

Run Django test suite with CockroachDB v26.3.0-rc.1: `$ ./tests/runtests.py --settings=test_roach migrations.test_loader --failfast -v 2`

The specific test that hangs when run like this passes in isolation:
```
$ ./tests/runtests.py --settings=test_roach migrations.test_loader.LoaderTests.test_loading_order_does_not_create_circular_dependency
```
**Expected behavior**

The test suite passes, as it does on earlier versions of CockroachDB.

**Environment:**
- CockroachDB version v26.3.0-rc.1

Jira issue: CRDB-66067

Epic CRDB-65516

Run ./tests/runtests.py --settings=test_roach migrations.test_loader --failfast -v 2 and compare it with the isolated LoaderTests.test_loading_order_does_not_create_circular_dependency run. Trace the migrations.test_loader test behavior under CockroachDB v26.3, then verify that the full test module completes without hanging or the replica GC threshold error.

Written by the indexing model from the issue text.