[quant][graphmode][refactor] rename SwapDequant and refactor code handling general ops (#37555)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/37555
Test Plan:
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Imported from OSS
Differential Revision: D21393514
fbshipit-source-id: 5bc9fa0f0be25f4c35a64acb23513f64ed07e230