[DCP][TNT] Updates test to use multi-threading

[LucasLLC]

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Summary: Updates dcp test to use multithreading. This PR is showing an error in CI. This test passes locally on a fresh checkout of tnt, but does not pass in CI. The error is related to a bug which was fixed in pytorch since: https://github.com/pytorch/pytorch/pull/119287

Test plan: Existing test