Fix regression for V09 test library handling.

detailed-1.0 test libraries allow users to define a test library as part
of package, which has a different package ID than the original library.
When I made the change to packageKey, I forgot to assign new package keys
here; the result was that the test library was compiled with the same
package key as the original.  The fix is a bit of a hack, since arguably
this should have been done properly in the configure step!

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>