Update the Angular/DI tests to latest from github.

third_party/pkg/angular/lib/mock/exception_handler.dart

Index: third_party/pkg/angular/lib/mock/exception_handler.dart
diff --git a/third_party/pkg/angular/lib/mock/exception_handler.dart b/third_party/pkg/angular/lib/mock/exception_handler.dart
index 7bcd17b89232f682f67174d44d38295e24a477e8..81823437b64fc5754ef7a101e7238fc0ed28e4ff 100644
--- a/third_party/pkg/angular/lib/mock/exception_handler.dart
+++ b/third_party/pkg/angular/lib/mock/exception_handler.dart
@@ -24,7 +24,7 @@ class LoggingExceptionHandler implements ExceptionHandler {
   /**
    * All exceptions are stored here for later examining.
    */
-  final List<ExceptionWithStack> errors = [];
+  final errors = <ExceptionWithStack>[];
 
   call(error, stack, [reason]) {
     errors.add(new ExceptionWithStack(error, stack));
@@ -36,7 +36,7 @@ class LoggingExceptionHandler implements ExceptionHandler {
    * to verify that all exceptions have been processed.
    */
   assertEmpty() {
-    if (errors.length > 0) {
+    if (errors.isNotEmpty) {
       throw new ArgumentError('Exception Logger not empty:\n$errors');
     }
   }