Merge pull request #9567 from kaspar030/unify_test_target

tests/pkg_tiny-asn1/Makefile

tests/pkg_tinycbor/Makefile

tests/pkg_tinycrypt/Makefile

tests/pkg_u8g2/Makefile

tests/pkg_ucglib/Makefile

tests/pkg_umorse/Makefile

tests/posix_semaphore/Makefile

tests/posix_time/Makefile

tests/ps_schedstatistics/Makefile

tests/pthread/Makefile

tests/pthread_barrier/Makefile

tests/pthread_cleanup/Makefile

tests/pthread_condition_variable/Makefile

tests/pthread_cooperation/Makefile

tests/pthread_rwlock/Makefile

tests/pthread_tls/Makefile

tests/rmutex/Makefile

tests/rng/Makefile

tests/sched_testing/Makefile

tests/shell/Makefile