[TensorExpr] Rename `Buffer` to `Placeholder`. (#45389)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/45389
Differential Revision: D23952866
Test Plan: Imported from OSS
Reviewed By: nickgg
Pulled By: ZolotukhinM
fbshipit-source-id: 17eedd3ac17897501403482ac1866c569d247c75
Author
Mikhail Zolotukhin
