Properly initialize element-transitioning array literals on ARM.

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 368ca5c3fa14908f808faaff021e1754b4fcc648..db9628bb05f539f40690abefa016e7822b808445 100644
--- a/src/arm/macro-assembler-arm.h
+++ b/src/arm/macro-assembler-arm.h
@@ -803,7 +803,8 @@ class MacroAssembler: public Assembler {
 
   // Check to see if maybe_number can be stored as a double in
   // FastDoubleElements. If it can, store it at the index specified by key in
-  // the FastDoubleElements array elements, otherwise jump to fail.
+  // the FastDoubleElements array elements. Otherwise jump to fail, in which
+  // case scratch2, scratch3 and scratch4 are unmodified.
   void StoreNumberToDoubleElements(Register value_reg,
                                    Register key_reg,
                                    Register receiver_reg,