embroider found a broken <link> in tests

Author: ef4

tests/index.html

@@ -11,7 +11,7 @@
     {{content-for "test-head"}}
 
     <link rel="stylesheet" href="{{rootURL}}assets/vendor.css">
-    <link rel="stylesheet" href="{{rootURL}}assets/ember-cli-htmlbars.css">
+    <link rel="stylesheet" href="{{rootURL}}assets/dummy.css">
     <link rel="stylesheet" href="{{rootURL}}assets/test-support.css">
 
     {{content-for "head-footer"}}