PPC/S390: Use Load Byte to fix endianess issue

src/builtins/s390/builtins-s390.cc

Index: src/builtins/s390/builtins-s390.cc
diff --git a/src/builtins/s390/builtins-s390.cc b/src/builtins/s390/builtins-s390.cc
index 42a8674d94e0863fea1a741e4bfa67fe78b166bb..856448f705ad701ac731f117a345a241fb70998d 100644
--- a/src/builtins/s390/builtins-s390.cc
+++ b/src/builtins/s390/builtins-s390.cc
@@ -2822,7 +2822,7 @@ static void CheckSpreadAndPushToStack(MacroAssembler* masm) {
   // For FastPacked kinds, iteration will have the same effect as simply
   // accessing each property in order.
   Label no_protector_check;
-  __ LoadP(scratch, FieldMemOperand(spread_map, Map::kBitField2Offset));
+  __ LoadlB(scratch, FieldMemOperand(spread_map, Map::kBitField2Offset));
   __ DecodeField<Map::ElementsKindBits>(scratch);
   __ CmpP(scratch, Operand(FAST_HOLEY_ELEMENTS));
   __ bgt(&runtime_call);