Separate unit test helper definitions bdw_and_later / xe_hp_and_later
Related-To: NEO-6466
Signed-off-by: Mateusz Jablonski <mateusz.jablonski@intel.com>
Dates corrected in copyright headers to reflect original publication date
(2018 for OpenCL, 2020 for Level Zero).
Signed-off-by: lgotszal <lukasz.gotszald@intel.com>