Fix incorrect comment

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Remove accidental NULL free in ason_ns_destroy

For some reason, before freeing a subspace, we were setting it to NULL, causing
breakage. I have no idea what this was supposed to be doing. At any rate,
problem solved.

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Generate better-filtered coverage data

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>