Switch XLA to only override abstract functions (#29636)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29636
This is a followup of li-roy 's work https://github.com/pytorch/pytorch/pull/23282. (I messed up the rebase there :(
After https://github.com/pytorch/xla/issues/1225 is done we are good to move the integration to only override abstract functions.
This PR contains a TODO which I'll remove in next 2 followup PRs.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29438
Reviewed By: ljk53
Differential Revision: D18445927
Pulled By: ailzhang
fbshipit-source-id: 52ea98626d6d6140241b5a4796a5c0d0c1b922ba
