Also fixes the problem where Mario can't jump if his base is overlapping a slope tile but he's not already standing on it. This is relevant if you have slopes that extend to the ground which Mario can walk through.
Tested with: Asar v1.71; SA-1 v1.32; Lunar Magic 3.04; snes9x 1.60.. somewhat.
This patch is up to the standards and requires no remoderation... problem is I only managed this once, and I forgot to get a gif... and haven't been able to cause this glitch to reproduce in reliable conditions again. So if anyone else can assist with that, because for now I can't remove the tag without solid proof it works.