Fix mir pass ICE in the presence of other errors

Author: oli-obk

compiler/rustc_mir_transform/src/abort_unwinding_calls.rs

@@ -41,6 +41,7 @@ impl<'tcx> MirPass<'tcx> for AbortUnwindingCalls {
             ty::Closure(..) => Abi::RustCall,
             ty::CoroutineClosure(..) => Abi::RustCall,
             ty::Coroutine(..) => Abi::Rust,
+            ty::Error(_) => return,
             _ => span_bug!(body.span, "unexpected body ty: {:?}", body_ty),
         };
         let body_can_unwind = layout::fn_can_unwind(tcx, Some(def_id), body_abi);