Clean up a few things:
a) Call scan-next-byte in hex.subx with the right number of args. Turns
out tests continue to work fine if they never use the other args.
b) Tear down a test for 'stop' in the right order. Not important since we
have no EBP to restore. But can still be misleading.
c) Have 'check-ints-equal' return nothing. Handy for it to not mess up
EAX. I never use the result anyway, and the name also is imperative suggesting
callers won't expect a return value.
Kartik Agaram