This simplifies the handling of the End node. Based on this CL we will
finally fix terminating every loop from the beginning (via Terminate
nodes) and fix inlining of Throw, Deoptimize and Terminate.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/1157023002

Cr-Commit-Position: refs/heads/master@{#28620}