[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/Analysis/LiveVariables.cpp b/clang/lib/Analysis/LiveVariables.cpp
index 4752c2b..f557a74 100644
--- a/clang/lib/Analysis/LiveVariables.cpp
+++ b/clang/lib/Analysis/LiveVariables.cpp
@@ -563,7 +563,7 @@
        it != ei; ++it) {
     vec.push_back(it->first);    
   }
-  std::sort(vec.begin(), vec.end(), [](const CFGBlock *A, const CFGBlock *B) {
+  llvm::sort(vec.begin(), vec.end(), [](const CFGBlock *A, const CFGBlock *B) {
     return A->getBlockID() < B->getBlockID();
   });
 
@@ -583,7 +583,8 @@
       declVec.push_back(*si);      
     }
 
-    std::sort(declVec.begin(), declVec.end(), [](const Decl *A, const Decl *B) {
+    llvm::sort(declVec.begin(), declVec.end(),
+               [](const Decl *A, const Decl *B) {
       return A->getLocStart() < B->getLocStart();
     });