create new variable defaultHwInfo as a std::unqiue_ptr<HardwareInfo>
replace platformDevices with defaultHwInfo in opencl/test/unit_test/api
Related-To: NEO-4499
Change-Id: I75b924e5b8a3a18f4ff9fdc3e598192569e102f7
Signed-off-by: Mateusz Jablonski <mateusz.jablonski@intel.com>