[turbofan] Move global constant optimization to AstGraphBuilder.

src/compiler/js-typed-lowering.cc

Index: src/compiler/js-typed-lowering.cc
diff --git a/src/compiler/js-typed-lowering.cc b/src/compiler/js-typed-lowering.cc
index 6e6432c572d9775a5e111639317dc30f2724e755..c165e999551244427c9f06a4ba3453ae477a0843 100644
--- a/src/compiler/js-typed-lowering.cc
+++ b/src/compiler/js-typed-lowering.cc
@@ -815,19 +815,6 @@ Reduction JSTypedLowering::ReduceJSToString(Node* node) {
 }
 
 
-Reduction JSTypedLowering::ReduceJSLoadGlobal(Node* node) {
-  // Optimize global constants like "undefined", "Infinity", and "NaN".
-  Handle<Name> name = LoadGlobalParametersOf(node->op()).name();
-  Handle<Object> constant_value = factory()->GlobalConstantFor(name);
-  if (!constant_value.is_null()) {
-    Node* constant = jsgraph()->Constant(constant_value);
-    ReplaceWithValue(node, constant);
-    return Replace(constant);
-  }
-  return NoChange();
-}
-
-
 Reduction JSTypedLowering::ReduceJSLoadNamed(Node* node) {
   DCHECK_EQ(IrOpcode::kJSLoadNamed, node->opcode());
   Node* receiver = NodeProperties::GetValueInput(node, 0);
@@ -1772,8 +1759,6 @@ Reduction JSTypedLowering::Reduce(Node* node) {
       return ReduceJSToNumber(node);
     case IrOpcode::kJSToString:
       return ReduceJSToString(node);
-    case IrOpcode::kJSLoadGlobal:
-      return ReduceJSLoadGlobal(node);
     case IrOpcode::kJSLoadNamed:
       return ReduceJSLoadNamed(node);
     case IrOpcode::kJSLoadProperty: