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

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@202635 91177308-0d34-0410-b5e6-96231b3b80d8
[C++11] Switch the clang-format LLVM style to use C++11 style braced
init list formatting. This suggestion has now gone into the LLVM coding
standards, and is particularly relevant now that we're using C++11.

Updated a really ridiculous number of tests to reflect this change.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@202637 91177308-0d34-0410-b5e6-96231b3b80d8