message: get rid of useless calls into `eval_lvalue`
diff: @@ -816,7 +816,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
  } else {
  let (def_id, substs) = self.resolve_associated_const(def_id, substs);
  let cid = GlobalId { def_id, substs, promoted: None };
  - self.read_lvalue(Lvalue::Global(cid))
  + self.globals.get(&cid).expect("static/const not cached").value
  }
  }
  @@ -826,7 +826,7 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
  substs: self.substs(),
  promoted: Some(index),
  };
  - self.read_lvalue(Lvalue::Global(cid))
  + self.globals.get(&cid).expect("promoted not cached").value
  }
  };
  