DCOM-243: 'Zend OPcache' PHP extension might prevent AnnotationReader from getting entity class comments

_From @doctrinebot on May 22, 2014 8:0_

Jira issue originally created by user VictorSmirnov:

If module `Zend OPcache` is installed and configured not to save comments the `AnnotationReader` class fails to parse data for entities.

Output from `php -m` contains line `Zend OPcache`.
The module is configured with the following parameter `opcache.save_comments=0`.

I would expect the `AnnotationReader` constructor to throw an exception. But it does not check if the module is loaded.

In addition to the check for `opcache` module

```
if (extension*loaded('opcache') && ini_get('opcache.save*comments') == 0) {
throw AnnotationException::optimizerPlusSaveComments();
}
```

we might have a new check for the `Zend OPcache` module

```
if (extension*loaded('Zend OPcache') && ini_get('opcache.save*comments') == 0) {
throw AnnotationException::optimizerPlusSaveComments();
}
```

_Copied from original issue: doctrine/common#551_