util: Convert the other architecture's m5 utility builds to scons.

util: Convert the other architecture's m5 utility builds to scons.

Because I don't have a canonical toolchain to set SPARC's defaults to,
it will by default build for Linux instead of Solaris like it used to.
This will make it hard to test, but without a compiler there's not much
I can do.

This also coincidentally brings the SPARC version more in line with the
other variants which all target Linux.

Change-Id: Ie19217e988782da124306160920f40ef168840e4
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/27219
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>