Update TEST_SPEED.cfg

[Vykori]

• Added extra safety measures
• Fixed typos and indentation inconsistencies
• Added extra movements to test moving one way, and then immediately back again
• Tested on Voron 0.2

[AndrewEllis93]

Thanks for the contribution. Some of the changes were intentional behaviors:

• The first G28 being unconditional is just a foolproofing measure. Your printer might still be "homed" but shifted from a previous test. We want to make sure to home again to ensure we're starting with a clean slate.

• The last G28 is a full XYZ home rather than G28 X Y intentionally, to fix an issue with Switchwire.

• The removed G90 after that is not necessary in most cases, but I put it there to account for people's poorly written homing_overrides, as a "just in case" sort of thing.

The safe speed and the additional stallguard delay look good. I might go even lower (max_velocity / 3 or 4 maybe?) but that's debatable

[Vykori]

Ooh good insight. I'll put those g-codes back in and re-submit

[Vykori]

I've added extra moves to the box and diagonal patterns to additionally test moving one way, then immediately moving back again. My thinking is the square_corner_velocity might get doubled-up in this type of movement.

Demo: https://youtu.be/kqPkX30OyF0

[Vykori]

Should this be two separate PRs? I'm new to Git things...