[SYCL][Graph] Add support for handler-less graph submission

[mmichel11]

• Adds submit_graph_direct_with_event_impl and submit_graph_direct_without_event_impl to the ABI which invoke a handler-less path for graph submission for queue::ext_oneapi_graph and the free function execute_graph.
• Adjusts handler-less submit_direct utility to be more general: support submissions which may contain host task, move scheduler bypass logic to callback functor, and parameterize submission CGType.
• Extends graph test coverage to cover identified gaps: recording handler-less graph submission and host task cases with dependencies.

[slawekptak]

I think that overall the changes look great. Added a few minor comments.

[reble]

LGTM

[mmichel11]

After sync with sycl, the L0 leak case no longer shows up for host_task_in_order_dependency, so I removed the xfail. A warning with older GCC versions was also fixed.