Delete libtorch test jobs (#46508)
Summary:
As they are noops for the 90+ days but still take 10min from start to finish:
https://github.com/pytorch/pytorch/blob/58f14d3a28159bb958ad2dced18e29ad0aa616bb/.jenkins/pytorch/test.sh#L376-L374
Pull Request resolved: https://github.com/pytorch/pytorch/pull/46508
Reviewed By: walterddr
Differential Revision: D24378877
Pulled By: malfet
fbshipit-source-id: 2e9990a8e1524ef39e891bb5ea874447eef34b31
