Patch from ARM Ltd.

BUG=none
TEST=added to test/cctest/test-disasm-arm.cc

Original review at http://codereview.chromium.org/7013024/.

Review URL: http://codereview.chromium.org/7013027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7875 ce2b1a6d-e550-0410-aec6-3dcde31c8c00