Demo and test multiple PID defaults (#19413)

Marlin/Configuration.h

   //#define PID_AUTOTUNE_MENU     // Add PID auto-tuning to the "Advanced Settings" menu. (~250 bytes of PROGMEM)
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-
-  // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it
-
-  // Ultimaker
-  #define DEFAULT_Kp 22.2
-  #define DEFAULT_Ki 1.08
-  #define DEFAULT_Kd 114
-
-  // MakerGear
-  //#define DEFAULT_Kp 7.0
-  //#define DEFAULT_Ki 0.1
-  //#define DEFAULT_Kd 12
-
-  // Mendel Parts V9 on 12V
-  //#define DEFAULT_Kp 63.0
-  //#define DEFAULT_Ki 2.25
-  //#define DEFAULT_Kd 440
-
+  #if ENABLED(PID_PARAMS_PER_HOTEND)
+    // Specify between 1 and HOTENDS values per array.
+    // If fewer than EXTRUDER values are provided, the last element will be repeated.
+    #define DEFAULT_Kp_LIST {  22.20,  20.0 }
+    #define DEFAULT_Ki_LIST {   1.08,   1.0 }
+    #define DEFAULT_Kd_LIST { 114.00, 112.0 }
+  #else
+    #define DEFAULT_Kp  22.20
+    #define DEFAULT_Ki   1.08
+    #define DEFAULT_Kd 114.00
+  #endif
 #endif // PIDTEMP
 
 //===========================================================================

buildroot/tests/BIGTREE_GTR_V1_0-tests

 opt_set TEMP_SENSOR_4 1
 opt_set TEMP_SENSOR_5 1
 opt_set NUM_Z_STEPPER_DRIVERS 3
-opt_enable TOOLCHANGE_FILAMENT_SWAP TOOLCHANGE_MIGRATION_FEATURE TOOLCHANGE_FS_INIT_BEFORE_SWAP TOOLCHANGE_FS_PRIME_FIRST_USED
+opt_set DEFAULT_Kp_LIST "{ 22.2, 20.0, 21.0, 19.0, 18.0, 17.0 }"
+opt_set DEFAULT_Ki_LIST "{ 1.08 }"
+opt_set DEFAULT_Kd_LIST "{ 114.0, 112.0, 110.0, 108.0 }"
+opt_enable TOOLCHANGE_FILAMENT_SWAP TOOLCHANGE_MIGRATION_FEATURE TOOLCHANGE_FS_INIT_BEFORE_SWAP TOOLCHANGE_FS_PRIME_FIRST_USED PID_PARAMS_PER_HOTEND
 exec_test $1 $2 "BigTreeTech GTR 6 Extruders Triple Z"
 
 # clean up