Rename the service tag 'kernel.event_subscriber' to just 'event_subscriber'

We use the tag 'kernel.event_subscriber' for registering subscriber services that need to be added to the event dispatcher. While most of the events that will get dispatched by our 'dispatcher' service will be kernel events, we'll also be using the same tag for other non-kernel-related events. So it makes sense to rename it to simply 'event_subscriber'.
This should be a simple find and replace (affecting services registered in core/lib/Drupal/Core/CoreBundle.php and the compiler pass itself in core/lib/Drupal/Core/DependencyInjection/Compiler/RegisterKernelListenersPass.php).

Any takers? :-)