[C++11] Replace llvm::next and llvm::prior with std::next and std::prev.

Remove the old functions.

llvm-svn: 202636
diff --git a/llvm/lib/IR/PassManager.cpp b/llvm/lib/IR/PassManager.cpp
index d6699f4..8185e55 100644
--- a/llvm/lib/IR/PassManager.cpp
+++ b/llvm/lib/IR/PassManager.cpp
@@ -123,7 +123,7 @@
   if (Inserted) {
     FunctionAnalysisResultListT &ResultList = FunctionAnalysisResultLists[F];
     ResultList.push_back(std::make_pair(PassID, lookupPass(PassID).run(F, this)));
-    RI->second = llvm::prior(ResultList.end());
+    RI->second = std::prev(ResultList.end());
   }
 
   return *RI->second->second;