[llvm] [NFC][SLP] Remove useless code of the schedule (PR #104697)

[Alexey Bataev via llvm-commits]

alexey-bataev wrote:

I think this functionality can be safely drop for now, please check https://reviews.llvm.org/D36518 to see what else can be removed

https://github.com/llvm/llvm-project/pull/104697