[DependencyInjection] Add the "kernel.close" tag to close services on kernel shutdown - #65989

As described in #65947, the kernel can reset services between requests but has no way to release the resources a service holds when it shuts down: bundles override Bundle::shutdown() and make a coordinating service public to do it.

This adds a kernel.close tag, mirroring kernel.reset:

$services->set('app.log_handler', StreamHandler::class)
    ->tag('kernel.close'); // calls close(), or pass ['method' => '...'] for another one

AbstractKernel::shutdown() closes the tagged services once the bundles are shut down, so reboot() and KernelTestCase::ensureKernelShutdown() release them too.

• Services are referenced with IGNORE_ON_UNINITIALIZED_REFERENCE: one that was never used is not instantiated just to be closed.
• method defaults to close, and on_invalid: ignore works as it does for kernel.reset.
• services_closer reuses ServicesResetter, which already skips uninitialized lazy objects and keeps closing the other services when one throws. The container is cleared even then.
• A non-shared service is rejected at compile time, since the container keeps no instance of it to close.

I went with kernel.close rather than kernel.shutdown because it names the action, as kernel.reset does. Happy to rename it, or to give the closer its own class if reusing the resetter reads oddly.