add testing of multiple copies to ci

Author: zloirock

package.json

@@ -119,8 +119,9 @@
     "test-unit-pure": "karma start -f=tests/bundles/pure.js",
     "test-unit-pure-standalone": "run-s init bundle-helpers bundle-tests-pure test-unit-pure",
     "test-unit-karma": "run-p test-unit-global test-unit-minified test-unit-pure",
-    "test-unit-node": "run-s test-unit-node-global test-unit-node-pure",
+    "test-unit-node": "run-p test-unit-node-global test-unit-node-pure test-unit-node-global-multiple-copies",
     "test-unit-node-global": "qunit packages/core-js-bundle/index.js tests/bundles/tests.js",
+    "test-unit-node-global-multiple-copies": "qunit packages/core-js-bundle/index.js packages/core-js-bundle/index.js tests/bundles/tests.js",
     "test-unit-node-pure": "qunit tests/bundles/pure.js",
     "test-promises": "run-s test-promises-aplus test-promises-es6",
     "test-promises-aplus": "promises-aplus-tests tests/promises-aplus/adapter --timeout 1000",