fix an appveyor issue with the test exit codes

.gitattributes

@@ -0,0 +1,6 @@
+# Line endings: enforce LF in GitHub, convert to native on checkout.
+* text=auto
+*.dart text
+*.md text
+*.sh text
+*.yaml text

appveyor.yml

@@ -13,4 +13,4 @@ clone_depth: 1
 build: off
 
 test_script:
-  - pub run grinder:grinder
+  - pub run grinder

tool/grind.dart

@@ -28,7 +28,10 @@ main(args) {
 analyze() => new PubApp.global('tuneup')..runAsync(['check', '--ignore-infos']);
 
 @Task()
-test() => new TestRunner().testAsync();
+test() {
+  //new TestRunner().testAsync();
+  return Dart.runAsync(getFile('test/all.dart').path, vmArgs: ['--checked']);
+}
 
 @Task('Apply dartfmt to all Dart source files')
 format() => DartFmt.format(existingSourceDirs);