Move Stepper::synchronize to Planner (#10713)

Co-Authored-By: ejtagle <ejtagle@hotmail.com>

Marlin/src/gcode/motion/G0_G1.cpp

@@ -84,7 +84,7 @@ void GcodeSuite::G0_G1(
         #define _MOVE_SYNC parser.seenval('Z')  // Only for Z move
       #endif
       if (_MOVE_SYNC) {
-        stepper.synchronize();
+        planner.synchronize();
         SERIAL_ECHOLNPGM(MSG_Z_MOVE_COMP);
       }
     #endif

Marlin/src/gcode/motion/G4.cpp

@@ -33,7 +33,7 @@ void GcodeSuite::G4() {
   if (parser.seenval('P')) dwell_ms = parser.value_millis(); // milliseconds to wait
   if (parser.seenval('S')) dwell_ms = parser.value_millis_from_seconds(); // seconds to wait
 
-  stepper.synchronize();
+  planner.synchronize();
   #if ENABLED(NANODLP_Z_SYNC)
     SERIAL_ECHOLNPGM(MSG_Z_MOVE_COMP);
   #endif