Minor cleanups & trivial refactoring related to Ast.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 49fd879bdc4f397062db5cf791668a2658cebf42..8486a8371c02bf858521da2d908344773119d1f2 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -9149,7 +9149,7 @@ void HOptimizedGraphBuilder::GenerateTypedArrayInitialize(
   CHECK_ALIVE(VisitForValue(arguments->at(kObjectArg)));
   HValue* obj = Pop();
 
-  if (arguments->at(kArrayIdArg)->node_type() != AstNode::kLiteral) {
+  if (arguments->at(kArrayIdArg)->IsLiteral()) {
     // This should never happen in real use, but can happen when fuzzing.
     // Just bail out.
     Bailout(kNeedSmiLiteral);
@@ -9176,7 +9176,7 @@ void HOptimizedGraphBuilder::GenerateTypedArrayInitialize(
   HValue* byte_offset;
   bool is_zero_byte_offset;
 
-  if (arguments->at(kByteOffsetArg)->node_type() == AstNode::kLiteral
+  if (arguments->at(kByteOffsetArg)->IsLiteral()
       && Smi::FromInt(0) ==
       *static_cast<Literal*>(arguments->at(kByteOffsetArg))->value()) {
     byte_offset = Add<HConstant>(static_cast<int32_t>(0));