Link libselinux/utils/base statically

CTS tests are not supposed to link against platform-private
libraries. As it is this test put an implicit requirement on
having libselinux.so in system image. Which is not intended.

Link statically against listed libraries to avoid such unintended
dependencies.

Test: make
Change-Id: I47a5b032000ee2c1ff764d6cc57683343851a07f