Driver: add support for linking the UBSan runtime library on Windows.

On Windows the user may invoke the linker directly, so we might not have an
opportunity to add runtime library flags to the linker command line. Instead,
instruct the code generator to embed linker directive in the object file
that cause the required runtime libraries to be linked.

We might also want to do something similar for ASan, but it seems to have
its own special complexities which may make this infeasible.

Differential Revision: http://reviews.llvm.org/D10862

llvm-svn: 241225