Set the current context to the function's context when entering to LAP.

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 5d213a3279949f54b5abda3ddf1a3f6633b57d77..1db509d0fec9488a94ddc3e988e8d387fde8db90 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -1350,6 +1350,10 @@ class MacroAssembler: public Assembler {
   void NegativeZeroTest(Register result, Register op1, Register op2,
                         Register scratch, Label* then_label);
 
+  // Machine code version of Map::GetConstructor().
+  // |temp| holds |result|'s map when done.
+  void GetMapConstructor(Register result, Register map, Register temp);
+
   // Find the function context up the context chain.
   void LoadContext(Register dst, int context_chain_length);