homing: Check homing distance to verify endstop trigger after retract

Instead of checking the endstop trigger directly after a retract move,
verify some distance is traveled during the following homing
operation.  This reduces the amount of synchronization between mcu and
host during homing.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/gcode.py

@@ -254,6 +254,8 @@ class GCodeParser:
         if not axes:
             axes = [0, 1, 2]
         homing_state = homing.Homing(self.toolhead, axes)
+        if self.inputfile:
+            homing_state.set_no_verify_retract()
         self.toolhead.home(homing_state)
         def axes_update(homing_state):
             newpos = self.toolhead.get_position()