Remove CLTDependency

I removed the usage of this in core in https://github.com/Homebrew/homebrew/commit/4028df4a5d192c56463dfbec723168d5b65231c6, https://github.com/Homebrew/homebrew/commit/cc62679924651a7b9c47abf518035b82039395bd, and https://github.com/Homebrew/homebrew/commit/3e07c615372bbf52bd8b28d41cbac3161d8c5abf. I'd like to remove it altogether as it's more of a bandaid than a real fix.