Commit 7ea5f5d2 changed how the lookahead queue is flushed.
Previously, the main flush timer would always run while the toolhead
was considered in an active state (print_time). After that commit,
the flush timer could sleep if there were no steps generated (no call
to note_mcu_movequeue_activity() ). This could lead to a situation
where a G4 command (or series of commands) could cause the toolhead to
be considered in an active state while the flush timer was disabled.
The result was that a future command may not be properly flushed (the
toolhead would fail to transition to a "Priming" state).
Fix by ensuring that all dwell() requests fully flush the lookahead
queue.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>