tests: add a stack printer test

Add a test to print out stack contents for SE mode programs.
The test will print out argc, argv, envp, and some auxiliary
vectors.

Change-Id: I489d752ee40fde24c531d8918d0c050f4df936c5
Reviewed-on: https://gem5-review.googlesource.com/3440
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>