PR #11165 causes an unnecessary regression; task_delete no longer works,
if the deleted task is from another group.
The logic that prevents this comes from:
nxnotify_cancellation() ->
tls_get_info_pid() ->
nxsched_get_stackinfo()
Which checks for permissions, which does not make sense in this case since
it is the kernel asking for the stack information.
Fix this by partially reverting 11165 and implementing a direct path for
the kernel to query for any tasks TLS.
57de6484e9