The iteration order over a std::set<Module*> depends on the addresses of the

The iteration order over a std::set<Module*> depends on the addresses of the
modules. Avoid that to make the order the linker sees the modules deterministic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148676 91177308-0d34-0410-b5e6-96231b3b80d8