[PATCH] xarray: port tests to kunit

[Sidhartha Kumar]

+ Liam, Matthew

Hello,

I believe this patch needs to be reverted for now as it breaks the 
user-space build of /tools/testing/radix-tree with:

In file included from xarray.c:11:
../../../lib/test_xarray.c:9:10: fatal error: kunit/test.h: No such file
or directory
      9 | #include <kunit/test.h>
        |          ^~~~~~~~~~~~~~
compilation terminated.
make: *** [<builtin>: xarray.o] Error 1
make: *** Waiting for unfinished jobs....

this then prevents the maple tree test suite from building.

Thanks,
Sid