Use failedAt in more places

pkg/compiler/lib/src/universe/selector.dart

Index: pkg/compiler/lib/src/universe/selector.dart
diff --git a/pkg/compiler/lib/src/universe/selector.dart b/pkg/compiler/lib/src/universe/selector.dart
index 661c8706a51e6b5172f0d352e5ac4433cb737cb4..6332157a1951af001cd4a65b5a15c74013a5113e 100644
--- a/pkg/compiler/lib/src/universe/selector.dart
+++ b/pkg/compiler/lib/src/universe/selector.dart
@@ -138,8 +138,7 @@ class Selector {
     } else if (element.isConstructor) {
       return new Selector.callConstructor(name);
     } else {
-      throw new SpannableAssertionFailure(
-          element, "Can't get selector from $element");
+      throw failedAt(element, "Can't get selector from $element");
     }
   }