ARM generated integer zero as either Operand(0, RelocInfo::NONE32), or
Operand(0), or Operand::Zero(). My change makes it use only
Operand::Zero().

This has no functional impact, it's pure cleanup.

R= ulan@chromium.org

Review URL: https://chromiumcodereview.appspot.com/11745030
Patch from JF Bastien <jfb@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13318 ce2b1a6d-e550-0410-aec6-3dcde31c8c00