Introduce PromiseRejectCallback.

R=aandrey@chromium.org, yurys@chromium.org, rossberg@chromium.org
API=v8::Isolate::SetPromiseRejectCallback, v8::Promise::HasHandler
LOG=Y
BUG=v8:3093

Review URL: https://codereview.chromium.org/600723005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24335 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix style nits in test

R=arv@chromium.org

Review URL: https://codereview.chromium.org/613253002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24336 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/master'