[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/lib/Transforms/Instrumentation/ControlHeightReduction.cpp b/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
index c08eb67..04bc614 100644
--- a/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
+++ b/llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
@@ -2070,7 +2070,7 @@
       getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
   RegionInfo &RI = getAnalysis<RegionInfoPass>().getRegionInfo();
   std::unique_ptr<OptimizationRemarkEmitter> OwnedORE =
-      llvm::make_unique<OptimizationRemarkEmitter>(&F);
+      std::make_unique<OptimizationRemarkEmitter>(&F);
   return CHR(F, BFI, DT, PSI, RI, *OwnedORE.get()).run();
 }