[npl] linux porting layer unit tests fail

[turon]

~/mynewt-nimble/porting/npl/linux/test$ make test
./test_npl_task.exe
All tests passed
./test_npl_callout.exe
All tests passed
./test_npl_eventq.exe
All tests passed
./test_npl_sem.exe
make: *** [Makefile:94: test] Segmentation fault

It may be good to add these tests as a github action that gates pull requests.

[turon]

Looks like this can be fixed by replacing main loop in test_os_sem.c:

BEFORE:

   while (1)
    {
        ble_npl_eventq_run(ble_npl_eventq_dflt_get());
    }

AFTER:

    while (1) {}

[sjanc]

hmm works for me for both 1.3 and master
[janc@ix test]$ make test
./test_npl_task.exe
All tests passed
./test_npl_callout.exe
All tests passed
./test_npl_eventq.exe
All tests passed
./test_npl_sem.exe
All tests passed