[clang] Change std::sort to llvm::sort in response to r327219

r327219 added wrappers to std::sort which randomly shuffle the container before
sorting.  This will help in uncovering non-determinism caused due to undefined
sorting order of objects having the same key.

To make use of that infrastructure we need to invoke llvm::sort instead of
std::sort.

llvm-svn: 328636
diff --git a/clang/lib/Frontend/DiagnosticRenderer.cpp b/clang/lib/Frontend/DiagnosticRenderer.cpp
index df426af..b6c9564 100644
--- a/clang/lib/Frontend/DiagnosticRenderer.cpp
+++ b/clang/lib/Frontend/DiagnosticRenderer.cpp
@@ -324,8 +324,8 @@
   SmallVector<FileID, 4> EndArgExpansions;
   getMacroArgExpansionFileIDs(Begin, BeginArgExpansions, /*IsBegin=*/true, SM);
   getMacroArgExpansionFileIDs(End, EndArgExpansions, /*IsBegin=*/false, SM);
-  std::sort(BeginArgExpansions.begin(), BeginArgExpansions.end());
-  std::sort(EndArgExpansions.begin(), EndArgExpansions.end());
+  llvm::sort(BeginArgExpansions.begin(), BeginArgExpansions.end());
+  llvm::sort(EndArgExpansions.begin(), EndArgExpansions.end());
   std::set_intersection(BeginArgExpansions.begin(), BeginArgExpansions.end(),
                         EndArgExpansions.begin(), EndArgExpansions.end(),
                         std::back_inserter(CommonArgExpansions));