[PTM] register aten::dequantize.self for spark spot int8 model
Summary: aten::dequantize.self is the only missing op in spark spot int8 model
Test Plan: same as D20761873
Reviewed By: iseeyuan
Differential Revision: D20785654
fbshipit-source-id: 19a3394370af58012ed0dedcc458f3633d921527
