Baritone when digging a custom size tunnel will repeatedly go off course

## Some information
Operating system: windows 10 64bit
Java version: Version 8 Update 241 (build 1.8.0_241-b07)
Minecraft version: 1.15.2
Baritone version: 1.5.2
Forge mods (if used): Impact is installed (not via forge)

## How to reproduce
- Attempt to build a very long custom tunnel `#tunnel 3 3 1000` with space to run around the tunnel (such as into a mountian with a way to go around)
- baritone will run around the tunnel

## video

[bbug.zip](https://github.com/cabaletta/baritone/files/4388335/bbug.zip)

## Modified settings

## my guess as to whats happening
judging by impact saying that it's "building clear area" im guessing that custom tunnels use the same code as the selection stuff, and this makes baritone try to path in weird ways to clear the rest of the selection
im not sure if custom tunnels without a depth paramater do this because they dont work #1451

## Final checklist
- [x] I know how to properly use check boxes
- [x] I have included the version of Minecraft I'm running, baritone's version and forge mods (if used).
- [x] I have included logs, exceptions and / or steps to reproduce the issue.
- [x] I have not used any OwO's or UwU's in this issue.