3 new value tests

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

This isn't terribly useful, was never documented or used internally, and was
throwing off our coverage numbers.

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Correctly set order in ason_reduce_list_intersect

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Silence compiler warnings in value.c

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