Use QTensor with quantized FC operator (#19541)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19541
For the quantized FC operator, replace the tuple (Tensor, scale, zero_point) with QTensor.
Differential Revision: D14900407
fbshipit-source-id: 164df38f3564e0a68af21b9fedaba98a44ca1453
