Disabling an ISR on ARM has 3 instructions of latency. A Memory barrier is REQUIRED to ensure proper and predictable disabling. Memory barriers are expensive, so avoid disabling if already disabled (See https://mcuoneclipse.com/2015/10/16/nvic-disabling-interrupts-on-arm-cortex-m-and-the-need-for-a-memory-barrier-instruction/)

Use macros that explicitly avoid double-evaluation and can be used for any datatype, replacing `min`, `max`, `abs`, `fabs`, `labs`, and `FABS`.

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

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

on the STM32 platform

A number of regressions were patched also. The UBL G29 P2 and P4 Press and Hold had stopped working. It is very possible this is broken in the bugfix_v1.1.x branch also.

The main purpose of the Pull Request is to get the 3-Point mesh tilting to use the LSF algorithm just like the grid based mesh tilt. This simplifies the logic and reduces the code size some what. But the real reason to do it is the 3-Point case can be solved exactly. And by feeding these numbers into the LSF algorithm it provides a way to check all that code for 'correctness'.

* Re-Print of same SD Memory Card file with single click

* Re-Print of same SD Memory Card file with single click
* This is the bugfix-v2.0.0 version of  https://github.com/MarlinFirmware/Marlin/pull/8104

Also, Max7219 debug code was used for this effort.   It has been
improved and hardened.

Setup FolgerTech i3-2020 Configuration files as a reference platform for
32-Bit work.

Also fix MAX7219 debug lights on 32-bit platforms.