Adds FrameAndConstantPoolScope and ConstantPoolUnavailableScope to enable
scoped management of constant pool availability.  Also load constant pool
pointer when entering an internal frame scope.

R=rodolph.perfetta@arm.com, ulan@chromium.org

Review URL: https://codereview.chromium.org/190793002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19858 ce2b1a6d-e550-0410-aec6-3dcde31c8c00