Enables eu thread scheduling mode override via the
INTERFACE_DESCRIPTOR_DATA and COMPUTE_WALKER.
Defines encodeEuSchedulingPolicy operating on INTERFACE_DESCRIPTOR_DATA
or Xe3 platform.
Adds tests verifying that thread scheduling mode can be overridden via
COMPUTE_WALKER.
Related-To: NEO-13771, HSD-18041256338, HSD-14013056398
Signed-off-by: Vysochyn, Illia <illia.vysochyn@intel.com>