tests: Add Makefiles for hello

This adds Makefiles for hello for ARM and x86 by leveraging docker and
dockcross. See https://github.com/dockcross/dockcross for more
information.

These Makefiles also allow for automatic uploading to the correct location
for users to download when running the new tests.

Change-Id: I7085000393cd5283502a7af362c85befda749181
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/4883

tests: Fix hello.c test program

Update the hello test to have a sane return code.

Change-Id: I9576b71ee995d8aa410c4ed19d44cc4e9fad10ee
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/4881
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

Add Alpha Linux version of "hello world" test.