DebugInfo: Do not include variables only referenced by templates in aranges.

ARanges included even extern variables referenced by pointer non-type
template parameters even though that variable isn't part of this
compilation unit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195895 91177308-0d34-0410-b5e6-96231b3b80d8