Split Promise API into Promise/Resolver

R=svenpanne@chromium.org
BUG=
LOG=Y

Review URL: https://codereview.chromium.org/196943014

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19972 ce2b1a6d-e550-0410-aec6-3dcde31c8c00