sh: Add a test trying to close a descriptor that is not open.
sh: Add a test trying to close a descriptor that is not open.

In stable/8 and older, this fails. Some of the redirection changes in head
have fixed it.

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