tests/linux: add a test case with conflicting cpusets to check insert errors

* 4th socket conflicts, ignored
* 3rd L3 conflicts, ignored
* core distance matrix conflicts, distance-core-groups ignored
* I/O affinity conflicts, cannot insert I/O group for hostbridge, attach to root

NUMA distance matrix works fine.

HWLOC_HIDE_ERRORS is set since error message go to stderr, we
can't check them anyway.