Get rid of DeviceAccessor wrapper, use raw pointers
Finishing the work started in 520676d6 (!3124 (merged)).
No performance impact on MI250X (ROCm 5.3.3, hipSYCL 0.9.4), but the code is cleaner now.
Refs #4719 (closed), #3895 (closed)
Edited by Andrey Alekseenko