Fix LoadFieldByIndex to take mutable heap-numbers into account.

src/arm/lithium-codegen-arm.h

Index: src/arm/lithium-codegen-arm.h
diff --git a/src/arm/lithium-codegen-arm.h b/src/arm/lithium-codegen-arm.h
index 21da500d011ede263898002ac7f34dcbb48b9d5a..38843f1719c173ed3ea687f5f3919dba6ab83747 100644
--- a/src/arm/lithium-codegen-arm.h
+++ b/src/arm/lithium-codegen-arm.h
@@ -141,6 +141,10 @@ class LCodeGen: public LCodeGenBase {
   void DoDeferredInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr,
                                        Label* map_check);
   void DoDeferredInstanceMigration(LCheckMaps* instr, Register object);
+  void DoDeferredLoadMutableDouble(LLoadFieldByIndex* instr,
+                                   Register result,
+                                   Register object,
+                                   Register index);
 
   // Parallel move support.
   void DoParallelMove(LParallelMove* move);