Fix cow fixed array map check in optimized arm code.

R=ager@chromium.org
BUG=
TEST=

Review URL: http://codereview.chromium.org/6814016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7544 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/lithium-codegen-arm.cc

@@ -2410,6 +2410,7 @@ void LCodeGen::DoLoadElements(LLoadElements* instr) {
     __ b(eq, &done);
     __ LoadRoot(ip, Heap::kFixedCOWArrayMapRootIndex);
     __ cmp(scratch, ip);
+    __ b(eq, &done);
     __ ldr(scratch, FieldMemOperand(result, HeapObject::kMapOffset));
     __ ldrb(scratch, FieldMemOperand(scratch, Map::kInstanceTypeOffset));
     __ sub(scratch, scratch, Operand(FIRST_EXTERNAL_ARRAY_TYPE));