Serialization for per channel qtensor (#26339)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26339
Serializes per-channel tensor in both torch.serialization and jit. Since we didn't bind Quantizer properly yet, I chose to save a tuple representing quantizer settings. To avoid recursive tensor serialization calls, I'm using tuple instead of tensor to store scales and zero points.
driazati - please check the serialization logic. Is there a good test that compares that JIT serialization and python serialization are equivalent? (I haven't tested it yet)
Test Plan: Imported from OSS
Differential Revision: D17443222
Pulled By: dzhulgakov
fbshipit-source-id: a34758de1ffd2ec1cdc5355f5baf95284a4ccf4b
