message: performance tests: make `routeChunkFor` more precise
  The previous substring match could include false positives in the
  performance entry name.
diff: @@ -67,7 +67,7 @@ describe('Performance test', () => {
  const routeChunkFor = function() {
  const chunkName = arguments[0];
  - return performance.getEntriesByType('resource').find(({name}) => name.endsWith('.js') && name.indexOf(chunkName) > -1);
  + return performance.getEntriesByType('resource').find(({name}) => name.endsWith('.js') && name.indexOf(`/${chunkName}`) > -1);
  };
  it(`downloads new bundle for ${routeName}`, async() => {
  