Add text representation for successor with a Block reference.
Add text representation for successor with a Block reference.

R=chrisha@chromium.org

Review URL: https://codereview.appspot.com/20160043

git-svn-id: db59699583a60be9a535cd09cdc9132301867226@1877 15e8cca8-e42c-11de-a347-f34a4f72eb7d

sebmarchand/syzygy,google/syzygy,ericmckean/syzygy,Eloston/syzygy,google/syzygy,wangming28/syzygy,Eloston/syzygy,ericmckean/syzygy,pombreda/syzygy,pombreda/syzygy,ericmckean/syzygy,supriyantomaftuh/syzygy,wangming28/syzygy,ericmckean/syzygy,wangming28/syzygy,supriyantomaftuh/syzygy,google/syzygy,supriyantomaftuh/syzygy,wangming28/syzygy,google/syzygy,sebmarchand/syzygy,supriyantomaftuh/syzygy,sebmarchand/syzygy,pombreda/syzygy,sebmarchand/syzygy,pombreda/syzygy,sebmarchand/syzygy,pombreda/syzygy,ericmckean/syzygy