[turbofan] Call FastNewContextStub for function context.

src/compiler/js-operator.cc

Index: src/compiler/js-operator.cc
diff --git a/src/compiler/js-operator.cc b/src/compiler/js-operator.cc
index 37369f697071067bfc29697f2bded2116959389b..02d5cebd9bd4d285ceaf98894895e451c058ebed 100644
--- a/src/compiler/js-operator.cc
+++ b/src/compiler/js-operator.cc
@@ -472,7 +472,6 @@ const CreateClosureParameters& CreateClosureParametersOf(const Operator* op) {
   V(ForInPrepare, Operator::kNoProperties, 1, 3)          \
   V(ForInStep, Operator::kPure, 1, 1)                     \
   V(StackCheck, Operator::kNoProperties, 0, 0)            \
-  V(CreateFunctionContext, Operator::kNoProperties, 1, 1) \
   V(CreateWithContext, Operator::kNoProperties, 2, 1)     \
   V(CreateModuleContext, Operator::kNoProperties, 2, 1)
 
@@ -773,6 +772,15 @@ const Operator* JSOperatorBuilder::CreateLiteralObject(int literal_flags) {
 }
 
 
+const Operator* JSOperatorBuilder::CreateFunctionContext(int slot_count) {
+  return new (zone()) Operator1<int>(                               // --
+      IrOpcode::kJSCreateFunctionContext, Operator::kNoProperties,  // opcode
+      "JSCreateFunctionContext",                                    // name
+      1, 1, 1, 1, 1, 2,                                             // counts
+      slot_count);                                                  // parameter
+}
+
+
 const Operator* JSOperatorBuilder::CreateCatchContext(
     const Handle<String>& name) {
   return new (zone()) Operator1<Handle<String>, Handle<String>::equal_to,