Reapply "Dispatch index_put_ to fill_ for scalar values (#188267 / #189105)" (#189303)

This reapplies #188267 / #189105 which has been reverted due to Meta internal CI failures. I also addressed https://github.com/pytorch/pytorch/pull/189105#issuecomment-4917329182

I will not merge it myself this time but leave it to @ngimel, @Skylion007, @izaitsevfb, or @atalman so the Meta internal CI failures can be dealt with.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/189303
Approved by: https://github.com/atalman, https://github.com/izaitsevfb

Co-authored-by: Andrey Talman <atalman@fb.com>