[ModuloSchedule] Devirtualize PeelingModuloScheduleExpander::expand a…

…s it's not needed

The use case is out of tree code deriving from this class - but without
a need to use the base class polymorphically, so skip the virtualization
and virtual dtor.

Post-commit review from 50ac7ce

llvm/include/llvm/CodeGen/ModuloSchedule.h

@@ -282,9 +282,8 @@ class PeelingModuloScheduleExpander {
                                 LiveIntervals *LIS)
       : Schedule(S), MF(MF), ST(MF.getSubtarget()), MRI(MF.getRegInfo()),
         TII(ST.getInstrInfo()), LIS(LIS) {}
-  virtual ~PeelingModuloScheduleExpander() {}
 
-  virtual void expand();
+  void expand();
 
   /// Runs ModuloScheduleExpander and treats it as a golden input to validate
   /// aspects of the code generated by PeelingModuloScheduleExpander.