Fix MSVC discarded return value warnings. NFC.

"C4858 This function constructs an object wrapped by a smart pointer and has no other effects; it is not useful to call this function and discard the return value."

Author: RKSimon

llvm/unittests/Analysis/MLModelRunnerTest.cpp

@@ -198,7 +198,7 @@ TEST(ReleaseModelRunner, ModelSelectorNoInputFeaturePresent) {
   LLVMContext Ctx;
   std::vector<TensorSpec> Inputs{TensorSpec::createSpec<int64_t>("a", {1}),
                                  TensorSpec::createSpec<int64_t>("b", {1})};
-  EXPECT_DEATH(std::make_unique<ReleaseModeModelRunner<AdditionAOTModel>>(
+  EXPECT_DEATH((void)std::make_unique<ReleaseModeModelRunner<AdditionAOTModel>>(
                    Ctx, Inputs, "", makeOptions().setModelSelector(M2Selector)),
                "A model selector was specified but the underlying model does "
                "not expose a model_selector input");
@@ -209,7 +209,7 @@ TEST(ReleaseModelRunner, ModelSelectorNoSelectorGiven) {
   std::vector<TensorSpec> Inputs{TensorSpec::createSpec<int64_t>("a", {1}),
                                  TensorSpec::createSpec<int64_t>("b", {1})};
   EXPECT_DEATH(
-      std::make_unique<ReleaseModeModelRunner<ComposedAOTModel>>(
+      (void)std::make_unique<ReleaseModeModelRunner<ComposedAOTModel>>(
           Ctx, Inputs, "", makeOptions()),
       "A model selector was not specified but the underlying model requires "
       "selecting one because it exposes a model_selector input");