Add test to ensure lld writes linked files to linked objects file for ThinLTO Indexing Only option.
Add test to ensure lld writes linked files to linked objects file for ThinLTO Indexing Only option.

Differential Revision: https://reviews.llvm.org/D46542


git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@331671 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld