Previously, HttpKernel performed request-stashing. By moving this to the Kernel class, the request is now available immediately after the kernel becomes aware of it. If the kernel is allowed to boot lazily (during the first call to handle()), this also allows an actual master Request to be available during booting.
The old "request" service definition (with a bogus class name) can be replaced with a factory-aware definition that retrieves the request directly from the kernel.
* removed the __call() method in Container: it means that now, there is only
one way to get a service: via the get() method;
* removed the $shared variable in the dumped Container classes (we now use
the $services variable from the parent class directly -- this is where we
have a performance improvement);
* optimized the PHP Dumper output.