Steamline test functionality

* Remove duplicate data types and structures
* Cleanup unused headers
* Move common CPU feature checkers to cpu_info

Signed-off-by: Anton Bondarenko <anton.bondarenko@arm.com>

Reviewed-by: Emil Ohlsson <emil.ohlsson@arm.com>
Approved-by: Emil Ohlsson <emil.ohlsson@arm.com>