[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/CodeGen/CGVTables.cpp b/clang/lib/CodeGen/CGVTables.cpp
index 4fb749f..d898417 100644
--- a/clang/lib/CodeGen/CGVTables.cpp
+++ b/clang/lib/CodeGen/CGVTables.cpp
@@ -992,8 +992,8 @@
                            AP.second.AddressPointIndex));
 
   // Sort the bit set entries for determinism.
-  std::sort(BitsetEntries.begin(), BitsetEntries.end(),
-            [this](const BSEntry &E1, const BSEntry &E2) {
+  llvm::sort(BitsetEntries.begin(), BitsetEntries.end(),
+             [this](const BSEntry &E1, const BSEntry &E2) {
     if (&E1 == &E2)
       return false;