fix(install): pick the .tar.gz Node.js archive when the host has no xz

`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

scripts/lib/node-bootstrap.sh

@@ -271,10 +271,13 @@ _nb_install_bundled_node() {
     esac
 
     local index_url="https://nodejs.org/dist/latest-v${HERMES_NODE_TARGET_MAJOR}.x/"
-    local tarball
-    tarball=$(curl -fsSL "$index_url" \
-        | grep -oE "node-v${HERMES_NODE_TARGET_MAJOR}\.[0-9]+\.[0-9]+-${node_os}-${node_arch}\.tar\.xz" \
-        | head -1)
+    local tarball=""
+    # `tar xf` needs the xz binary for .tar.xz; minimal images ship tar without it (#11197).
+    if command -v xz >/dev/null 2>&1; then
+        tarball=$(curl -fsSL "$index_url" \
+            | grep -oE "node-v${HERMES_NODE_TARGET_MAJOR}\.[0-9]+\.[0-9]+-${node_os}-${node_arch}\.tar\.xz" \
+            | head -1)
+    fi
     if [ -z "$tarball" ]; then
         tarball=$(curl -fsSL "$index_url" \
             | grep -oE "node-v${HERMES_NODE_TARGET_MAJOR}\.[0-9]+\.[0-9]+-${node_os}-${node_arch}\.tar\.gz" \