Add max/min/argmax/argmin/sort/argsort for quantized Tensor (#21546)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21546
Added following methods for QTensor:
- max, min
- argmax, argmin
- sort, argsort
Reviewed By: dzhulgakov
Differential Revision: D15718117
fbshipit-source-id: 746b978d5722cb75e216fc65585bf206d45a7969
