Attempt to fix flaky test_structseq_repr (#20931)
Summary:
Previously, this used `crepr` afer the decref of `repr`. This is not
allowed because `repr` owns the cached copy of `crepr`.
Let's see if this fixes the contbuild.
See #20926
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20931
Differential Revision: D15501929
Pulled By: colesbury
fbshipit-source-id: 24141ba62df8758d2a3998cf7c2054be09088b6a
