tools: prefer gz or bz2 tarballs

tools: prefer gz or bz2 tarballs

In the light of recent XZ events, and fundamental XZ issues lets work on
moving away from using XZ.

So, use gz compressed tarballs as sources whenever possible.

dwarves only offers bz2 compressed tarballs, so use those as size
difference is minor compared to XZ.

Signed-off-by: Robert Marko <robimarko@gmail.com>
dwarves