MLECO-3149: Add CTest driven FVP runs for non-native targets.

Additional CMake configuration parameters required:

* `BUILD_FVP_TESTS`: Selects whether these tests are built, OFF by default.
* `FVP_PATH`: Path to the FVP that MUST be provided for the configuration to succeed.

Change-Id: I741379cd0a6078a3e2c3163e6b253b2f5dc25c58
Signed-off-by: Sarah Blades <sarah.blades@arm.com>