KWSys: Build tests after libraries

The TestSharedForward executable and TestDynload module do not actually
link to a KWSys library, but it is nice to build them after the
libraries just like all other test binaries.

This also works around a universal binary bug in Xcode 2.x.  It forgets
to create the output directory for the executable before linking it.  We
avoid the problem by putting the library in the directory first.