Revert obsolete llvm-link -preserve-modules option/test

This testing mode is now obsolete with the change to linkInModule
to take a std::unique_ptr to Module.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258399 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed