test for rtems_workspace_greedy_allocate

[Chris Johns]

Hello,

I see the call `rtems_workspace_greedy_allocate` is in `src/rtems` and publicly
available via the installed header file `rtems/support.h`.

Are there tests for this and similar support calls?

I ask because tests in rtems.git and rtems-libbsd.git testsuites depend on this
call and it appears to be broken on psim and PowerPC hardware. Recent psim test
results from Joel show `spprivenv01.exe` failing and I think it is
`rtems_workspace_greedy_allocate` or friends that maybe the issue ..

https://lists.rtems.org/pipermail/build/2021-February/025169.html

Thanks
Chris