Fix KeypointRCNN test (#39589)
Summary:
Since Argmax is updated in ONNX Runtime we can enable testing for all output, including keypoints_scores.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39589
Reviewed By: hl475
Differential Revision: D21992264
Pulled By: houseroad
fbshipit-source-id: a390b4628d2ac290902b9e651c69d47db9be540f
