[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/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index ad65f6f..92fb8f0 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -1474,11 +1474,11 @@
   // deterministic order. We could sort in any way, but we chose
   // case-insensitive sorting for consistency with the -help option
   // which prints out options in the case-insensitive alphabetical order.
-  std::sort(SuggestedCompletions.begin(), SuggestedCompletions.end(),
-            [](StringRef A, StringRef B) {
-              if (int X = A.compare_lower(B))
-                return X < 0;
-              return A.compare(B) > 0;
+  llvm::sort(SuggestedCompletions.begin(), SuggestedCompletions.end(),
+             [](StringRef A, StringRef B) {
+               if (int X = A.compare_lower(B))
+                 return X < 0;
+               return A.compare(B) > 0;
             });
 
   llvm::outs() << llvm::join(SuggestedCompletions, "\n") << '\n';