[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

llvm/utils/TableGen/CodeGenDAGPatterns.cpp

@@ -3101,7 +3101,7 @@ void CodeGenDAGPatterns::ParsePatternFragments(bool OutFrags) {
 
     ListInit *LI = Frag->getValueAsListInit("Fragments");
     TreePattern *P =
-        (PatternFragments[Frag] = llvm::make_unique<TreePattern>(
+        (PatternFragments[Frag] = std::make_unique<TreePattern>(
              Frag, LI, !Frag->isSubClassOf("OutPatFrag"),
              *this)).get();