Revert "Ensure the $HOME env is being set on Windows"

This reverts commit 52028fc3bc.

internal/homefix/homefix.go

@@ -1,5 +0,0 @@
-// Package homefix exists to address a bug where mvdan.cc/sh expects
-// $HOME to be available in order to be able to expand "~".
-//
-// We should delete this package once this is fixed there.
-package homefix

internal/homefix/homefix_windows.go

@@ -1,15 +0,0 @@
-package homefix
-
-import (
-	"os"
-
-	"github.com/mitchellh/go-homedir"
-)
-
-func init() {
-	if os.Getenv("HOME") == "" {
-		if home, err := homedir.Dir(); err == nil {
-			os.Setenv("HOME", home)
-		}
-	}
-}