Remove scratch register requirement from LoadInstanceDescriptors on arm and mips.

src/arm/macro-assembler-arm.h

Index: src/arm/macro-assembler-arm.h
diff --git a/src/arm/macro-assembler-arm.h b/src/arm/macro-assembler-arm.h
index c7032bafb162e3d24e84eba83bddea70165a697f..35935c14d7ad6b8748fe212e29902b596fe817b4 100644
--- a/src/arm/macro-assembler-arm.h
+++ b/src/arm/macro-assembler-arm.h
@@ -1281,9 +1281,7 @@ class MacroAssembler: public Assembler {
                           DoubleRegister temp_double_reg);
 
 
-  void LoadInstanceDescriptors(Register map,
-                               Register descriptors,
-                               Register scratch);
+  void LoadInstanceDescriptors(Register map, Register descriptors);
   void EnumLength(Register dst, Register map);
   void NumberOfOwnDescriptors(Register dst, Register map);