Revert D31591512: .github: Enable onnx tests
Test Plan: revert-hammer
Differential Revision:
D31591512 (https://github.com/pytorch/pytorch/commit/06a156efc75f726ca95cadc043bab0c0d75d7548)
Original commit changeset: 4a8bb3f0e62f
fbshipit-source-id: 2d8580c0e507c2a0b30431bcf30eb01cef82f602
