[llvm] [RISCV] Do not check PostRAScheduler in enablePostRAScheduler (PR #92781)

[Craig Topper via llvm-commits]

topperc wrote:

This patch is failing 2 tests

LLVM :: CodeGen/RISCV/machine-combiner.ll

LLVM :: CodeGen/RISCV/short-forward-branch-opt.ll

https://github.com/llvm/llvm-project/pull/92781