[llvm] [AArch64] Enable RT and partial unrolling with reductions for Apple CPUs. (PR #149699)

[Jonathan Cohen via llvm-commits]

https://github.com/jcohen-apple commented:

Only had one small comment. It would be nice to have some remark when we bail out on unrolling reductions so we could get some statistics on that, but I don't think it has to be in this PR.

https://github.com/llvm/llvm-project/pull/149699