Commit e05c6354 changed the internal step compress queue from 64bit
integers to 32bit integers. However, that commit broke the proactive
flushing of moves that could produce more than 64K steps. This could
lead to large memory allocations and cpu slow downs on printers that
had a very large Z axis - possibly leading to a "Timer too close" mcu
shutdown. Correct the code so that it properly generates a 64bit
flush clock.
Also, be sure to only expand / memmove the queue when there is no room
for a new element at the end.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
6d6638826c