Add obj2yaml to test dependencies

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178852 91177308-0d34-0410-b5e6-96231b3b80d8
Buildbot fix for r178851: mistake was in wrong TargetRegisterInfo::getRegClass usage.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178854 91177308-0d34-0410-b5e6-96231b3b80d8