disable source maps for unit testing

workaround for known bug in Angular CLI
angular/angular-cli#7296

Author: Jan Jelschen

package.json

@@ -30,8 +30,8 @@
     "ng": "ng",
     "start": "ng serve -H 0.0.0.0 --preserve-symlinks",
     "build": "ng build --prod",
-    "test": "ng test",
-    "test:once": "ng test --single-run",
+    "test": "ng test -sm=false",
+    "test:once": "ng test --single-run -sm=false",
     "lint": "ng lint",
     "pree2e": "webdriver-manager update --ignore_ssl --gecko=false",
     "e2e": "ng e2e",