Add EXPECT_SLICE_EMPTY macro
Add EXPECT_SLICE_EMPTY macro

Kind of like memset. It's useful for checking that manipulating the page frame
bitmap has no unintended side effects.

awensaunders/kernel-of-truth,Herbstein/kernel-of-truth,iankronquist/kernel-of-truth,Herbstein/kernel-of-truth,awensaunders/kernel-of-truth,iankronquist/kernel-of-truth,awensaunders/kernel-of-truth,iankronquist/kernel-of-truth,iankronquist/kernel-of-truth,Herbstein/kernel-of-truth,iankronquist/kernel-of-truth