* 5.1:
  [FrameworkBundle] Fix MicroKernelTrait for php 8
  [DependencyInjection] Fixed tests for wither with static return type.
  [HttpFoundation] Avoid TypeError when calling \SessionHandlerInterface::gc().
  Don't call method_exists() with non-objects.
  [Lock] skip tests when ext-mongo is not installed
  [HttpClient] Adjust AmpResponse to the stricter trait handling in php 8.
  [FrameworkBundle] don't use abstract methods in MicroKernelTrait, their semantics changed in PHP 8