MIPS: Properly initialize element-transitioning array literals on ARM.

Port r10624 (172d021).

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/9689010
Patch from Daniel Kalmar <kalmard@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11074 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/code-stubs-mips.cc

@@ -7677,7 +7677,7 @@ void StoreArrayLiteralElementStub::Generate(MacroAssembler* masm) {
   // Array literal has ElementsKind of FAST_DOUBLE_ELEMENTS.
   __ bind(&double_elements);
   __ lw(t1, FieldMemOperand(a1, JSObject::kElementsOffset));
-  __ StoreNumberToDoubleElements(a0, a3, a1, t1, t2, t3, t5, t6,
+  __ StoreNumberToDoubleElements(a0, a3, a1, t1, t2, t3, t5, a2,
                                  &slow_elements);
   __ Ret(USE_DELAY_SLOT);
   __ mov(v0, a0);

src/mips/macro-assembler-mips.h

@@ -945,7 +945,8 @@ 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,