does not work: make the test build-pass for the opt revision

Author: RalfJung

tests/ui/consts/required-consts/collect-in-dead-vtable.no-opt.stderr

@@ -1,13 +1,13 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/collect-in-dead-vtable.rs:11:19
+  --> $DIR/collect-in-dead-vtable.rs:10:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-vtable.rs:11:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-vtable.rs:10:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: the above error was encountered while instantiating `fn <std::vec::Vec<i32> as MyTrait>::not_called`
-  --> $DIR/collect-in-dead-vtable.rs:34:40
+  --> $DIR/collect-in-dead-vtable.rs:33:40
    |
 LL |         let gen_vtable: &dyn MyTrait = &v; // vtable "appears" here
    |                                        ^^

tests/ui/consts/required-consts/collect-in-dead-vtable.rs

@@ -1,8 +1,7 @@
-//@revisions: no-opt
-//FIXME: `opt` revision currently does not stop with an error due to
-//<https://github.com/rust-lang/rust/issues/107503>.
-//@ build-fail
+//@revisions: no-opt opt
+//@[no-opt] build-fail
 //@[opt] compile-flags: -O
+//@[opt] build-pass
 //! Make sure we detect erroneous constants post-monomorphization even when they are unused. This is
 //! crucial, people rely on it for soundness. (https://github.com/rust-lang/rust/issues/112090)