[optimizing] trivial x86 explicit null check fix

Change a cmp reg,0 to test reg,reg.  I don't know that this code
is even invoked.

Change-Id: Ifddffcb22d8a4060b7abbea17d8e7168535e409b
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>
1 file changed