Debug info - generalize namespace test to not depend on a DW_TAG_file_type entry
Debug info - generalize namespace test to not depend on a DW_TAG_file_type entry

This isn't necessary & with the next change to LLVM the DW_TAG_file_type entry
won't be emitted at all - only the raw filename/directory pair, so match on
that directly instead.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@177609 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang