[tensorexpr] Add BufMap instruction to reuse the memory of dest buf for src buf (#66451)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/66451
Test Plan: Imported from OSS
Reviewed By: navahgar, ZolotukhinM
Differential Revision: D31557190
Pulled By: huiguoo
fbshipit-source-id: 96e08a05cb1c558706c4189e27d5d72efbd9c510
