[TensorExpr] Change API for creating Load and Store expressions. (#45520)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45520
With this change `Load`s and `Store`s no longer accept `Placeholder`s in
their constructor and `::make` functions and can only be built with
`Buf`.
`Placeholder` gets its own `store`, `load`, `storeWithMask`, and
`loadWithMask` method for more convenient construction.
Test Plan: Imported from OSS
Reviewed By: glaringlee
Differential Revision: D23998789
Pulled By: ZolotukhinM
fbshipit-source-id: 3fe018e00c1529a563553b2b215f403b34aea912
Author
Mikhail Zolotukhin
