For cpu's with Neon, set arm as well.  Make unittest allow testdata unaccessable but try proc/cpuinfo
BUG=none
TEST=none
Review URL: https://webrtc-codereview.appspot.com/610005

git-svn-id: http://libyuv.googlecode.com/svn/trunk@273 16f28f9a-4ce2-e073-06de-1de4eb20be90