[AArch64] Don't enable the post-RA MI scheduler at OptNone.

Hopefully, this will appease the bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217712 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/AArch64/AArch64TargetMachine.cpp

@@ -129,6 +129,7 @@ class AArch64PassConfig : public TargetPassConfig {
 public:
   AArch64PassConfig(AArch64TargetMachine *TM, PassManagerBase &PM)
       : TargetPassConfig(TM, PM) {
+    if (TM->getOptLevel() != CodeGenOpt::None)
       substitutePass(&PostRASchedulerID, &PostMachineSchedulerID);
   }