Added test scenario that triggers the
"panic: softdep_deallocate_dependencies: dangling deps"

Sponsored by:	EMC / Isilon storage division
Added the option of an external filter script for syscall tests.

Sponsored by:	EMC / Isilon storage division
Only run ipcrm(1) for the user "nobody".
Exclude thr_create() from tests.

Sponsored by:	EMC / Isilon storage division