Fix #10256

Do the Z lift normally before setting Z back to its prior value. But do the Z lower using spoofing. This should produce proper symmetrical movement.

This ensures that steppers that share an enable pin will only be disabled for a miniscule time.

See https://github.com/MarlinFirmware/Marlin/issues/10246#issuecomment-377146936

Pending a more complete solution to tool-change Z deviation.

Followup to #10250

[2.0.x] Improvements to general and delta homing

Followup to 436e5b7

Some languages will need to be updated for proper phrasing

Followup to 3007eee

Fixes #10137

See 941e9bd329 (commitcomment-28262166)

Fixes #10209

Fix #10232

From #10204 by @adriancuzman

- And implement the `backtrace()` function call

The `_O2` attribute is no longer needed on the malyanlcd function, and the macros have broken timer numbers - reset this to a function to return the right device. Also fix the bit order cast in SPI.

From #10234 by @thopiekar

[2.0.x] DUE: Several fixes to the backtracker

Based on #10216

[2.0.x] Fix TMC sanity checks that always fail

[2.0.x] DUE debugging: Solve WDT startup delay, add traceback & crash report uses programming port baud rate