[ELF] llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...)

Summary: The convenience wrapper in STLExtras is available since rL342102.

Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, mgrang, llvm-commits

Differential Revision: https://reviews.llvm.org/D52569

llvm-svn: 343146