Update outdated deadlock detection test

[awaelchli]

What does this PR do?

Fixes #15418

The recent version of torchrun/torchelastic has a deadlock detection which kills all processes if one of them exits while others in the group perform collective operations. This means that this bypasses our own deadlock detection for which we test. So the test does no longer make sense :( However, we also have a test for the non torchelastic casek test_ddp_terminate_when_deadlock_is_detected which still covers all cases of ddp without torchelastic.

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cc @Borda @justusschock @awaelchli @akihironitta