Fix dart2js-with-kernel test crashes

pkg/compiler/lib/src/kernel/element_map_mixins.dart

Index: pkg/compiler/lib/src/kernel/element_map_mixins.dart
diff --git a/pkg/compiler/lib/src/kernel/element_map_mixins.dart b/pkg/compiler/lib/src/kernel/element_map_mixins.dart
index 0edad4c27fd24d4be4fab60d00a9c5b2a1d31d5f..14b3b827f3c8220f456c0ef44b88886bab9e6089 100644
--- a/pkg/compiler/lib/src/kernel/element_map_mixins.dart
+++ b/pkg/compiler/lib/src/kernel/element_map_mixins.dart
@@ -142,6 +142,7 @@ abstract class KernelToElementMapBaseMixin implements KernelToElementMap {
       type ??= findIn(Uris.dart_web_sql);
       type ??= findIn(Uris.dart_indexed_db);
       type ??= findIn(Uris.dart_typed_data);
+      type ??= findIn(Uris.dart_mirrors);
       if (type == null && required) {
         reporter.reportErrorMessage(CURRENT_ELEMENT_SPANNABLE,
             MessageKind.GENERIC, {'text': "Type '$typeName' not found."});