[quant] fill_ path for quantized tensors (#43303)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/43303
Test Plan: Imported from OSS
Reviewed By: raghuramank100
Differential Revision: D23231947
Pulled By: z-a-f
fbshipit-source-id: fd5110ff15a073f326ef590436f8c6e5a2608324
