LCheckSmi sometimes has a result register and sometimes not, even though its
LTemplateInstruction alwasys has room for one. Debug output use HasResult to
determine whether it was ok to de-ref result(), but HasResult doesn't check for
the case where LTemplateInstruction has a result but it's NULL.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/21037004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15931 ce2b1a6d-e550-0410-aec6-3dcde31c8c00