This enables us to produce the list of eager inner functions for compilation
in one go during the outer function's renumbering step, and avoid having
to do renumbering explicitly on the inner functions, simplifying the zone
ownership.

BUG=v8:5203, v8:5215

Review-Url: https://codereview.chromium.org/2648503002
Cr-Commit-Position: refs/heads/master@{#42540}