Drop pgm_read_*_near and let headers choose (#12301)

- Drop `pgm_read_*_near` and let headers choose.
- Define `USE_EXECUTE_COMMANDS_IMMEDIATE` as a conditional.
- Add `process_subcommands_now` for SRAM-based commands.

Marlin/src/module/motion.h

@@ -95,8 +95,8 @@ extern int16_t feedrate_percentage;
 
 extern float soft_endstop_min[XYZ], soft_endstop_max[XYZ];
 
-FORCE_INLINE float pgm_read_any(const float *p) { return pgm_read_float_near(p); }
-FORCE_INLINE signed char pgm_read_any(const signed char *p) { return pgm_read_byte_near(p); }
+FORCE_INLINE float pgm_read_any(const float *p) { return pgm_read_float(p); }
+FORCE_INLINE signed char pgm_read_any(const signed char *p) { return pgm_read_byte(p); }
 
 #define XYZ_DEFS(type, array, CONFIG) \
   extern const type array##_P[XYZ]; \