test: adjust for the move to MIR-based const checking.

src/test/compile-fail/check-static-values-constraints.rs

@@ -140,4 +140,5 @@ static STATIC19: Box<isize> =
 pub fn main() {
     let y = { static x: Box<isize> = box 3; x };
     //~^ ERROR allocations are not allowed in statics
+    //~^^ ERROR cannot move out of static item
 }