message: test(common): change fallback default URL in MockPlatformLocation
  In node@16 the URL constructor fails for for a malformed URL such as http://<empty>/. Instead is
  used as this conveys the same information in tests but is correctly formed.
  PR Close
diff: @@ -122,7 +122,7 @@ export class MockPlatformLocation implements PlatformLocation {
  this.baseHref = config.appBaseHref || '';
  const parsedChanges =
  - this.parseChanges(null, config.startUrl || 'http://<empty>/', this.baseHref);
  + this.parseChanges(null, config.startUrl || 'http://_empty_/', this.baseHref);
  this.urlChanges[0] = {...parsedChanges};
  }
  }
  