message: fix crash with NNaN fncalls
diff: @@ -460,7 +460,7 @@ StateValue FnAttrs::encode(State &s, StateValue &&val, const Type &ty,
  Value *allocalign) const {
  if (has(FnAttrs::NNaN)) {
  assert(ty.isFloatType());
  - val.non_poison &= !val.value.isNaN();
  + val.non_poison &= !ty.getAsFloatType()->getFloat(val.value).isNaN();
  }
  if (ty.isPtrType())
  