setUp and tearDown do not appear to work in the browser

Steps to reproduce:
1. Go into the examples/browser folder
2. Open test.html
3. Everything works as expected
4. Add setUp and tearDown functions to suite1.js
5. Refresh the page to rerun the tests

_Defect_: the functions added in step 4 are run just like normal tests

This appears to be a defect in the copy of `nodeunit.js` in the examples/browser folder. The example's version of nodeunit.js has a function `wrapGroup` but this is never called; whereas the node-based `nodeunit.js` in lib/core.js does call this.

(Sorry that I don't understand the code base well enough at the moment to offer a patch.)

Comienza con examples/browser/test.html, examples/browser/suite1.js y la copia para navegador de nodeunit.js; después, compara su gestión de wrapGroup con lib/core.js. Actualiza test.html después de añadir setUp y tearDown para confirmar que los hooks se tratan como setup y teardown, y no como pruebas normales; el ejemplo del navegador debería ejecutarse sin informarlos como pruebas.

Escrito por el modelo de indexación a partir del texto del issue.