intel: aubinator: enable loading dumps from standard input

intel: aubinator: enable loading dumps from standard input

In conjuction with an intel_aubdump change, you can now look at your
application's output like this :

$ intel_aubdump -c '/path/to/aubinator --gen=hsw' my_gl_app

v2: Add print_help() comment about standard input handling (Eero)
    Remove shrinked gtt space debug workaround (Eero)

v3: Use realloc rather than memcpy/free (Ben)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Sirisha Gandikota <Sirisha.Gandikota@intel.com>