Remove unnecessary ob_end_clean() from template tests

Another pull request to get [VisualPHPUnit](https://github.com/NSinopoli/VisualPHPUnit) working. Thanks to @NSinopoli for this one: 

https://github.com/NSinopoli/VisualPHPUnit/issues/84#issuecomment-12464116

> ob_get_clean() essentially executes both ob_get_contents() and ob_end_clean().
> I'm not sure why those tests are calling ob_end_clean() immediately after ob_get_clean(). As a result, VPU's output buffer is getting clobbered.


If anyone's interested in running VisualPHPUnit locally let me know and I can help with the configuration.