[turbofan] Call FastNewContextStub for function context.

src/compiler/js-typed-lowering.h

Index: src/compiler/js-typed-lowering.h
diff --git a/src/compiler/js-typed-lowering.h b/src/compiler/js-typed-lowering.h
index c11f068e5b24265c2a31e9b7cccdf67d768a4706..71f940798cd728f56f47bc7ec36b40d7eb06e847 100644
--- a/src/compiler/js-typed-lowering.h
+++ b/src/compiler/js-typed-lowering.h
@@ -61,6 +61,7 @@ class JSTypedLowering final : public AdvancedReducer {
   Reduction ReduceJSCreateClosure(Node* node);
   Reduction ReduceJSCreateLiteralArray(Node* node);
   Reduction ReduceJSCreateLiteralObject(Node* node);
+  Reduction ReduceJSCreateFunctionContext(Node* node);
   Reduction ReduceJSCreateWithContext(Node* node);
   Reduction ReduceJSCreateBlockContext(Node* node);
   Reduction ReduceJSCallFunction(Node* node);
@@ -85,6 +86,7 @@ class JSTypedLowering final : public AdvancedReducer {
   MachineOperatorBuilder* machine() const;
 
   // Limits up to which context allocations are inlined.
+  static const int kFunctionContextAllocationLimit = 16;
   static const int kBlockContextAllocationLimit = 16;
 
   JSGraph* jsgraph_;