[Clang] 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.

Differential revision: https://reviews.llvm.org/D66259

llvm-svn: 368942
diff --git a/clang/tools/clang-refactor/TestSupport.cpp b/clang/tools/clang-refactor/TestSupport.cpp
index 7d5d547..9d2d966 100644
--- a/clang/tools/clang-refactor/TestSupport.cpp
+++ b/clang/tools/clang-refactor/TestSupport.cpp
@@ -256,7 +256,7 @@
 
 std::unique_ptr<ClangRefactorToolConsumerInterface>
 TestSelectionRangesInFile::createConsumer() const {
-  return llvm::make_unique<TestRefactoringResultConsumer>(*this);
+  return std::make_unique<TestRefactoringResultConsumer>(*this);
 }
 
 /// Adds the \p ColumnOffset to file offset \p Offset, without going past a