Reland and fix "Fix LoadFieldByIndex to take mutable heap-numbers into account.""

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index c280999ca2b0849d7710fa89814d9ae472de7aa4..ba44b509e1cc9f3d2e81b4131957e8f5ec513c0b 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -2539,7 +2539,9 @@ LInstruction* LChunkBuilder::DoCheckMapValue(HCheckMapValue* instr) {
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
-  return DefineAsRegister(new(zone()) LLoadFieldByIndex(object, index));
+  LLoadFieldByIndex* load = new(zone()) LLoadFieldByIndex(object, index);
+  LInstruction* result = DefineSameAsFirst(load);
+  return AssignPointerMap(result);
 }
 
 } }  // namespace v8::internal