Enable native_dropout/backward for lazy (#69374)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69374
Enables existing native_dropout operator for use with lazy tensors. Also adds aten interned strings so lazy tensor codegen can refer to the symbols in generated IR classes.
Test Plan: CI for regressions of existing use cases, and manual tests of new Lazy Tensor functionality
Reviewed By: ngimel
Differential Revision: D32837301
fbshipit-source-id: a372a24ec65367fb84ad2e97c7e38cae4ec703a6
