MFC r269977
MFC r269977

Skip pgrep-j and pkill-j if jail or jls is not installed.

Even though jail is part of the base system, it can be disabled by src.conf
settings. Therefore, it should be listed as a required program for tests that
use it.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase