GlobalOpt: FileCheck-ize test

No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212103 91177308-0d34-0410-b5e6-96231b3b80d8
GlobalOpt: Don't swap private for internal linkage

There were transforms whose *intent* was to downgrade the linkage of
external objects to have internal linkage.

However, it fired on things with private linkage as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212104 91177308-0d34-0410-b5e6-96231b3b80d8