Optimize more linkonce_odr values during LTO.

When a linkonce_odr value that is on the dso list is not unnamed_addr
we can still look to see if anything is actually using its address. If
not, it is safe to hide it.

This patch implements that by moving GlobalStatus to Transforms/Utils
and using it in Internalize.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193090 91177308-0d34-0410-b5e6-96231b3b80d8