Fix `extract` method to avoid recalculating count() for each iteration.

Cache the value of `count($attributes)` to avoid recalculating it for each iteration of the loop.

Since this count will never change during the method execution, this change make the code a bit more efficient.
Merge branch '2.2' into 2.3

* 2.2:
  updated VERSION for 2.2.11
  update CONTRIBUTORS for 2.2.11
  updated CHANGELOG for 2.2.11
  [HttpKernel] made a small optimization to Bundle initialization
  minor optimalization at bundle initialization
  [EventDispatcher] tweaked README
  removed observer pattern, in favour of mediator
  [DoctrineBridge] normalized class names in the ORM type guesser
  Fix `extract` method to avoid recalculating count() for each iteration.
  use the correct class name to retrieve mapped class' metadata and repository
  [WebProfilerBundle] Fixed js escaping in time.html.twig

Conflicts:
	src/Symfony/Bundle/WebProfilerBundle/Resources/views/Collector/time.html.twig
	src/Symfony/Component/HttpKernel/Kernel.php
Merge branch '2.3' into 2.4

* 2.3:
  updated VERSION for 2.2.11
  update CONTRIBUTORS for 2.2.11
  updated CHANGELOG for 2.2.11
  Fixed typo in phpdoc
  Handled the scenario when no entity manager is passed with closure query builder.
  [HttpKernel] made a small optimization to Bundle initialization
  minor optimalization at bundle initialization
  [EventDispatcher] tweaked README
  removed observer pattern, in favour of mediator
  [DoctrineBridge] normalized class names in the ORM type guesser
  Fix `extract` method to avoid recalculating count() for each iteration.
  [Debug] ensured that a fatal PHP error is actually fatal after being handled by our error handler
  use the correct class name to retrieve mapped class' metadata and repository
  [WebProfilerBundle] Fixed js escaping in time.html.twig

Conflicts:
	src/Symfony/Component/Debug/ErrorHandler.php