Bootstrap cannot remove host symlink on Windows if created from WSL2

[ChrisDenton]

If I use ./x in WSL2 it will create a host symlink in the build directory. If I then switch to the Windows host using the same build directory I get this error:

thread 'main' panicked at 'fs::remove_dir(&host) failed with The directory name is invalid. (os error 267)', lib.rs:516:13
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

The simplest solution here would be to detect ERROR_DIRECTORY (aka os error 267) and fallback to fs::remove_file.