Fix XOutput/XOutputTensor for ivalue based c2 operators (#17599)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/17599
XOutput/XOutputTensor was broken for ivalue based operators. This diff fixes that.
Reviewed By: ezyang
Differential Revision: D14274003
fbshipit-source-id: b99f020244c66c4e2551dbd32ae0f665cc91b338
