fix(guix-bootstrap): split bootstrap exec xz from static-binaries, use xz 5.0.6, just give it a try to solve problem

steps-guix/improve/bootstrap-exec-xz-i686-linux.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+set -e
+
+dist="${DISTFILES:-/external/distfiles}"
+xz_src="/bootstrap-seeds/xz-5.0.6/bin/xz"
+xz_dst="${dist}/bootstrap-exec-xz-i686-linux"
+
+if [ ! -x "${xz_src}" ]; then
+    echo "Missing required bootstrap seed executable: ${xz_src}" >&2
+    exit 1
+fi
+
+install -D -m 0755 "${xz_src}" "${xz_dst}"