[llvm] Migrate llvm::make_unique to std::make_unique

Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013
diff --git a/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h b/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h
index 56a3926..511f038 100644
--- a/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h
+++ b/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h
@@ -135,8 +135,8 @@
 createPairedQueueChannels() {
   auto Q1 = std::make_shared<Queue>();
   auto Q2 = std::make_shared<Queue>();
-  auto C1 = llvm::make_unique<QueueChannel>(Q1, Q2);
-  auto C2 = llvm::make_unique<QueueChannel>(Q2, Q1);
+  auto C1 = std::make_unique<QueueChannel>(Q1, Q2);
+  auto C2 = std::make_unique<QueueChannel>(Q2, Q1);
   return std::make_pair(std::move(C1), std::move(C2));
 }