We don't need to convert to strings, we can compare directly. This removes the final
use of the index arrays.
This of course changes the order of returned routes, which alters test_real_biases, since
that biases against the final channel in the *first* route.
Took me far too long to diagnose that!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
7c7a4f8795