ARM64: fix operator precedence issue.

As a result the constant pool marker was always 0.

BUG=
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/350923003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21987 ce2b1a6d-e550-0410-aec6-3dcde31c8c00