[commit] info-macros.exp: Pass "debug" to prepare_for_testing

[Joel Brobecker]

> This test was failing under Fission when run with the full testsuite and
> passing when run by itself.
> I test Fission with a board file which sets debug_flags,
> but debug_flags doesn't get used unless "debug" is passed as a build option.
> So when run by itself "options" was "" and thus the Fission compilation
> flags weren't getting picked up, but I guess when run with the full testsuite
> this test was picking up a value of options that contained "debug".

Perhaps we could start resetting all the global variables that
we know of before starting each testcase. That would help prevent
one testcase influencing the next... It should be relatively easy
to do, I think, we just need the list of globals.

-- 
Joel