This splits the SuperReference AST node into SuperPropertyReference and
SuperCallReference. The super call reference node consists of three
unresolved vars to this, new.target and this_function. These gets
declared when the right function is entered and if it is in use. The
variables gets assigned in FullCodeGenerator::Generate.

BUG=v8:3768
LOG=N
R=wingo@igalia.com, adamk@chromium.org

Review URL: https://codereview.chromium.org/1146863007

Cr-Commit-Position: refs/heads/master@{#28731}