Fixed test retry in browsers.

packages/tests/karma-reporter.js

@@ -40,7 +40,9 @@ const KarmaReporter = function () {
       lastSuite = result.suite[0];
     }
 
-    runner.emit('test');
+    runner.emit('test', {
+        _currentRetry: 0
+    });
 
     if (result.skipped) {
       runner.emit('skipped');

rollup-tests.config.js

@@ -83,6 +83,7 @@ export default commandLineArgs => {
         format: format,
         name: "testing"
       },
+      context: "window",
       treeshake: false,
       plugins: plugins
   };