erroneous_const span now changes with inlining

Author: RalfJung

tests/compile-fail/erroneous_const.rs

@@ -1,5 +1,7 @@
 //! Make sure we detect erroneous constants post-monomorphization even when they are unused.
 //! (https://github.com/rust-lang/miri/issues/1382)
+// Inlining changes the error location
+// compile-flags: -Zmir-opt-level=0
 #![feature(const_panic)]
 #![feature(never_type)]
 #![warn(warnings, const_err)]