This removes the deprecated generator support for resumable functions
from {FullCodeGenerator}. The existing {AstNumbering} heuristic already
triggers Ignition for most resumable functions, with this change we make
said heuristic a hard choice and remove the deprecated code. This also
has the advantage that any suspended {JSGeneratorObject} instance on the
heap is guaranteed to have code based on a bytecode array.

R=bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/2504223002
Cr-Commit-Position: refs/heads/master@{#41135}