ConstProp: drop pass

now obsolete!

Results for the whole series are excellent:

Difference at 95.0% confidence
	-3.97603% +/- 0.254656%

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>

FEXCore/Source/Interface/IR/PassManager.h

@@ -43,7 +43,6 @@ protected:
 };
 
 class PassManager final {
-  friend class ConstProp;
 public:
   void AddDefaultPasses(FEXCore::Context::ContextImpl* ctx);
   void AddDefaultValidationPasses();