[turbofan] Remove locally constructed simplified builders.

src/compiler/js-builtin-reducer.cc

Index: src/compiler/js-builtin-reducer.cc
diff --git a/src/compiler/js-builtin-reducer.cc b/src/compiler/js-builtin-reducer.cc
index 49ed031182dc254832476fe6559e36e211394679..426a707acaf112cfc2551e982544336aa3cf00bd 100644
--- a/src/compiler/js-builtin-reducer.cc
+++ b/src/compiler/js-builtin-reducer.cc
@@ -7,6 +7,7 @@
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
+#include "src/compiler/simplified-operator.h"
 #include "src/objects-inl.h"
 #include "src/types.h"
 
@@ -87,9 +88,7 @@ class JSCallReduction {
 
 
 JSBuiltinReducer::JSBuiltinReducer(Editor* editor, JSGraph* jsgraph)
-    : AdvancedReducer(editor),
-      jsgraph_(jsgraph),
-      simplified_(jsgraph->zone()) {}
+    : AdvancedReducer(editor), jsgraph_(jsgraph) {}
 
 
 // ECMA-262, section 15.8.2.11.
@@ -184,6 +183,11 @@ MachineOperatorBuilder* JSBuiltinReducer::machine() const {
   return jsgraph()->machine();
 }
 
+
+SimplifiedOperatorBuilder* JSBuiltinReducer::simplified() const {
+  return jsgraph()->simplified();
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8