Interp runs ahead of motion.  This test checks various state after
aborting a program that switches coordinate systems within the program.

Interp's state must be synched from the status channel after an abort.
If this breaks, MDI command motion, mode line settings and system
parameters will follow interp's idea of state, which is probably that
where the program had run to a queue buster or to exit, whichever
comes first, whereas preview DROs and origin will match the status
channel's idea of state, which is that of the running program just
prior to the abort.

This test runs a program that starts in G55 and aborts during a slow
move; were the program to continue, it would switch to G56 before
hitting a queue buster.  Before program run, coordinate systems are
given distinct settings so that after aborting, status channel and
interp offsets can be checked in various ways.