Modified depends() to recognize that when all levels are "=" and

Modified depends() to recognize that when all levels are "=" and
there's no possible loo-independent dependence, then there's no
dependence.

Updated all test result appropriately.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168719 91177308-0d34-0410-b5e6-96231b3b80d8