cleanup scons test rules for validator proofs a bit.
cleanup scons test rules for validator proofs a bit.

R=kschimpf@google.com

Review URL: https://codereview.chromium.org/761493005

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@14174 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client