zero_smp: Change a compile time error to a test_skip
zero_smp: Change a compile time error to a test_skip

In 8d1f2c1, we changed the default assumption to be that all ctests are build.
This change allows the test to gracefully skip if it does not have 'native SMP'
threads.

arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi