build: speed up source tarball creation

Avoid building the node binary when building the source tarball. We
need a node binary to build the docs, but it doesn't have to be one
we build from scratch and can reuse any available node binary.

Skip building the xz compressed tarball in the build-tarball workflow
as we only use the gzip compressed tarball in the subsequent build
jobs.

PR-URL: https://github.com/nodejs/node/pull/34508


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Zeyu Yang <himself65@outlook.com>