const_prop no longer does ptr-to-int casts

Author: RalfJung

src/test/mir-opt/const_prop/reify_fn_ptr.rs

@@ -19,7 +19,7 @@ fn main() {
 //      _3 = const Scalar(AllocId(1).0x0) : fn();
 //      _2 = move _3 as usize (Misc);
 //      ...
-//      _1 = const Scalar(AllocId(1).0x0) : *const fn();
+//      _1 = move _2 as *const fn() (Misc);
 //      ...
 //  }
 // END rustc.main.ConstProp.after.mir