Suppress "erroneous constant used" for constants tainted by errors

When constant evaluation fails because its MIR is tainted by errors,
suppress note indicating that erroneous constant was used, since those
errors have to be fixed regardless of the constant being used or not.

compiler/rustc_trait_selection/src/traits/auto_trait.rs

@@ -801,7 +801,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
                                             span: tcx.def_span(unevaluated.def),
                                             unevaluated: unevaluated,
                                         });
-                                    Err(ErrorHandled::Reported(reported))
+                                    Err(ErrorHandled::Reported(reported.into()))
                                 }
                                 Err(err) => Err(err),
                             }