Second stage of implementing an out-of-line constant pool on Arm.  This CL
Introduces the ConstantPoolArray object which will be used as the backing
store of out-of-line constant pools.  Nothing uses this object yet.

BUG=
R=ulan@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22601003

Patch from Ross McIlroy <rmcilroy@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17197 ce2b1a6d-e550-0410-aec6-3dcde31c8c00