[runtime] Store constructor function index on primitive maps.

src/mips/builtins-mips.cc

Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index f4a47238d0319d7dbcfbffb51b969665b3cee60a..e27199a904f9adc655c7c3eace7b5f5e15293130 100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -440,7 +440,10 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                   Operand(Map::kSlackTrackingCounterEnd));
 
         // Allocate object with a slack.
-        __ lbu(a0, FieldMemOperand(a2, Map::kInObjectPropertiesOffset));
+        __ lbu(
+            a0,
+            FieldMemOperand(
+                a2, Map::kInObjectPropertiesOrConstructorFunctionIndexOffset));
         __ lbu(a2, FieldMemOperand(a2, Map::kUnusedPropertyFieldsOffset));
         __ subu(a0, a0, a2);
         __ sll(at, a0, kPointerSizeLog2);