Structured Kernels for `index_copy`, add `out` variant (#67329)
Summary:
This PR ports `index_copy` implementation to structured kernels, also adds an `out` variant.
~Note to the reviewers: This is in draft mode, waiting for the tests from the CI, and I'll give a final look before requesting the review.~
Issue tracker: https://github.com/pytorch/pytorch/issues/55070
cc: bdhirsh ysiraichi
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67329
Reviewed By: ejguan
Differential Revision: D34077219
Pulled By: bdhirsh
fbshipit-source-id: 6accda33957f654b753261c5c3d765a27a64d2c0
(cherry picked from commit f3ac83217ad62b537b47a8ceb7ae7edf1ad6ec5e)
