[quant][graphmode][fix] dequantize propagation for {add/mul}_scalar (#40596)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/40596
Previously the fusion patterns for {add/mul}_scalar is inconsistent since the op pattern
produces a non-quantized tensor and the op replacement graph produces a quantized tensor
Test Plan: Imported from OSS
Differential Revision: D22251072
fbshipit-source-id: e16eb92cf6611578cca1ed8ebde961f8d0610137
