Add capability to build OSAL code coverage tests as part of build

[skliper]

Is your feature request related to a problem? Please describe.
Currently code coverage testing for OSAL is not integrated with the cfe build system. It's possible to build separately, but then care has to be taken to match configurations and extra steps are required.

Describe the solution you'd like
Build OSAL code coverage (of the shared and target OSAL) executables for the host when "ENABLE_UNIT_TESTS" is true, using the osconfig.h defined for the build (vs default in the BSP).

Describe alternatives you've considered
It's possible to build stand alone, but not trivial.

Additional context
None

Requester Info
Jacob Hageman - NASA/GSFC

[skliper]

Duplicate of nasa/osal#362, no changes needed in cFE