force_move: Implement CLEAR for SET_KINEMATIC_POSITION (#6262)

`CLEAR` clears the homing status (resets the axis limits) without turning off
the motors. This is particularly useful when implementing safe Z homing in
`[homing_override]` on printers with multiple independent Z steppers (where
`FORCE_MOVE` can't be used).

Signed-off-by: Dennis Marttinen <twelho@welho.tech>

klippy/kinematics/corexy.py

@@ -43,9 +43,10 @@ class CoreXYKinematics:
             rail.set_position(newpos)
             if i in homing_axes:
                 self.limits[i] = rail.get_range()
-    def note_z_not_homed(self):
-        # Helper for Safe Z Home
-        self.limits[2] = (1.0, -1.0)
+    def clear_homing_state(self, axes):
+        for i, _ in enumerate(self.limits):
+            if i in axes:
+                self.limits[i] = (1.0, -1.0)
     def home(self, homing_state):
         # Each axis is homed independently and in order
         for axis in homing_state.get_axes():
@@ -63,7 +64,7 @@ class CoreXYKinematics:
             # Perform homing
             homing_state.home_rails([rail], forcepos, homepos)
     def _motor_off(self, print_time):
-        self.limits = [(1.0, -1.0)] * 3
+        self.clear_homing_state((0, 1, 2))
     def _check_endstops(self, move):
         end_pos = move.end_pos
         for i in (0, 1, 2):