`tar xf node-*.tar.xz` shells out to the xz binary; minimal Debian, DietPi
and WSL images ship tar without it, so extraction died mid-way and the
installer then failed on a missing directory. Select .tar.xz only when
`xz` is on PATH, in both the installer and the runtime node bootstrap.
Same approach as the earlier #4229 (@JoshuaMart) and #39541 (@karnull);
#11278 (@vominh1919) attempted an apt-only install of xz-utils instead.
Refs #11197
a7cf8ef8b2