Move DescriptorArray into the map

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 49849d8c493e617a172ee7d122895ff8c5686c60..ee0635f91fa3352bb54d7e0c8e4c3efb8e2dc33a 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -2905,28 +2905,7 @@ void MacroAssembler::LoadUint32(XMMRegister dst,
 
 void MacroAssembler::LoadInstanceDescriptors(Register map,
                                              Register descriptors) {
-  Register temp = descriptors;
-  movq(temp, FieldOperand(map, Map::kTransitionsOrBackPointerOffset));
-
-  Label ok, fail, load_from_back_pointer;
-  CheckMap(temp,
-           isolate()->factory()->fixed_array_map(),
-           &fail,
-           DONT_DO_SMI_CHECK);
-  movq(descriptors, FieldOperand(temp, TransitionArray::kDescriptorsOffset));
-  jmp(&ok);
-
-  bind(&fail);
-  CompareRoot(temp, Heap::kUndefinedValueRootIndex);
-  j(not_equal, &load_from_back_pointer, Label::kNear);
-  Move(descriptors, isolate()->factory()->empty_descriptor_array());
-  jmp(&ok);
-
-  bind(&load_from_back_pointer);
-  movq(temp, FieldOperand(temp, Map::kTransitionsOrBackPointerOffset));
-  movq(descriptors, FieldOperand(temp, TransitionArray::kDescriptorsOffset));
-
-  bind(&ok);
+  movq(descriptors, FieldOperand(map, Map::kDescriptorsOffset));
 }