`no-install` does not look for a local tool path

[allan2]

When calling with --mode no-install, wasm-pack currently bails.
src_install_mod.rs

pub fn get_tool_path(status: &Status, tool: Tool) -> Result<&Download> {
    match status {
        Status::Found(download) => Ok(download),
        Status::CannotInstall => bail!("Not able to find or install a local {}.", tool),
        install::Status::PlatformNotSupported => {
            bail!("{} does not currently support your platform.", tool)
        }
    }
}

It should look for the relevant tool on the local system before bailing.

This will enable packaging wasm-pack without vendored wasm-bindgen, such as on distros where wasm-bindgen is packaged separately.

I have a PR ready. Waiting for #1531