Remove usages of alloca() according to style guide.

src/compiler/ast-graph-builder.cc

Index: src/compiler/ast-graph-builder.cc
diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index afc58e91454b95a560c96ebdca3c57ca838b8bef..5ad8269ca9a19c1f6eec61fc86d2621870a509ab 100644
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -1652,7 +1652,7 @@ void AstGraphBuilder::VisitLogicalExpression(BinaryOperation* expr) {
 
 Node* AstGraphBuilder::ProcessArguments(Operator* op, int arity) {
   DCHECK(environment()->stack_height() >= arity);
-  Node** all = info()->zone()->NewArray<Node*>(arity);  // XXX: alloca?
+  Node** all = info()->zone()->NewArray<Node*>(arity);
   for (int i = arity - 1; i >= 0; --i) {
     all[i] = environment()->Pop();
   }