Follow up to the previous commit. Stop decreasing --ab-loop-count=N on
each iteration so it is preserved across different loops. In particular
it is preserved between different files without adding it to
--reset-on-next-file. Add a property to expose the remaning A-B loop
count instead.
The current behavior of --ab-loop-count=N is even worse than --loop-file
since it also doesn't reset when defining a new A-B loop in the same
file. Defining it has no effect after --ab-loop-count has decreased to
0, and this can't be fixed by adding it to --reset-on-next-file. This
commit also resets remaining-ab-loops every time --ab-loop-a and
--ab-loop-b are set to fix this.