[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/Target/WebAssembly/WebAssemblyMCInstLower.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp
index 26baac3..647e987 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp
@@ -115,7 +115,7 @@
     getLibcallSignature(Subtarget, Name, Returns, Params);
   }
   auto Signature =
-      make_unique<wasm::WasmSignature>(std::move(Returns), std::move(Params));
+      std::make_unique<wasm::WasmSignature>(std::move(Returns), std::move(Params));
   WasmSym->setSignature(Signature.get());
   Printer.addSignature(std::move(Signature));
 
@@ -238,7 +238,7 @@
           }
 
           auto *WasmSym = cast<MCSymbolWasm>(Sym);
-          auto Signature = make_unique<wasm::WasmSignature>(std::move(Returns),
+          auto Signature = std::make_unique<wasm::WasmSignature>(std::move(Returns),
                                                             std::move(Params));
           WasmSym->setSignature(Signature.get());
           Printer.addSignature(std::move(Signature));