MIPS: port Fix problem with arguments object ICs not checking for dictionary mode elements.

Ported r8497 (916120a)

Patch by Daniel Kalmar <kalmard@homejinni.com>

BUG=
TEST=

Review URL: http://codereview.chromium.org//7329013
Patch from Paul Lind <plind44@gmail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8586 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/ic-mips.cc

@@ -854,6 +854,9 @@ static MemOperand GenerateUnmappedArgumentsLookup(MacroAssembler* masm,
   const int kBackingStoreOffset = FixedArray::kHeaderSize + kPointerSize;
   Register backing_store = parameter_map;
   __ lw(backing_store, FieldMemOperand(parameter_map, kBackingStoreOffset));
+  Handle<Map> fixed_array_map(masm->isolate()->heap()->fixed_array_map());
+  __ CheckMap(backing_store, scratch, fixed_array_map, slow_case,
+              DONT_DO_SMI_CHECK);
   __ lw(scratch, FieldMemOperand(backing_store, FixedArray::kLengthOffset));
   __ Branch(slow_case, Ugreater_equal, key, Operand(scratch));
   __ li(scratch, Operand(kPointerSize >> 1));