test.h: add assert_not_equal_*()
test.h: add assert_not_equal_*()

This test helper was conspicuously missing, so this patch just adds it
at the obvious place.

Signed-off-by: Peter Jones <2e0a021e603479ff81838c00c3b770daca4e0214@redhat.com>

rhinstaller/shim,rhinstaller/shim,rhinstaller/shim