Arrange Z2 min before Z2 max

Marlin/stepper.cpp

   #if ENABLED(Z_DUAL_ENDSTOPS)
     #define Z_APPLY_STEP(v,Q) \
     if (performing_homing) { \
-      if (Z_HOME_DIR > 0) {\
-        if (!(TEST(endstops.old_endstop_bits, Z_MAX) && (count_direction[Z_AXIS] > 0)) && !locked_z_motor) Z_STEP_WRITE(v); \
-        if (!(TEST(endstops.old_endstop_bits, Z2_MAX) && (count_direction[Z_AXIS] > 0)) && !locked_z2_motor) Z2_STEP_WRITE(v); \
-      } \
-      else { \
+      if (Z_HOME_DIR < 0) { \
         if (!(TEST(endstops.old_endstop_bits, Z_MIN) && (count_direction[Z_AXIS] < 0)) && !locked_z_motor) Z_STEP_WRITE(v); \
         if (!(TEST(endstops.old_endstop_bits, Z2_MIN) && (count_direction[Z_AXIS] < 0)) && !locked_z2_motor) Z2_STEP_WRITE(v); \
       } \
+      else { \
+        if (!(TEST(endstops.old_endstop_bits, Z_MAX) && (count_direction[Z_AXIS] > 0)) && !locked_z_motor) Z_STEP_WRITE(v); \
+        if (!(TEST(endstops.old_endstop_bits, Z2_MAX) && (count_direction[Z_AXIS] > 0)) && !locked_z2_motor) Z2_STEP_WRITE(v); \
+      } \
     } \
     else { \
       Z_STEP_WRITE(v); \