Introduce a ResumeGeneratorTrampoline, which does the actual stack state
reconstruction (currently always restores a fullcodegen frame), and
introduce appropriate TurboFan builtins for %GeneratorPrototype%.next,
%GeneratorPrototype%.return and %GeneratorPrototype%.throw based on
this native builtin.

Also unify the flooding in case of step-in to always work based on
JSFunction and remove the special casing for JSGeneratorObject.

R=mstarzinger@chromium.org, neis@chromium.org
TBR=rossberg@chromium.org
BUG=chromium:513471
LOG=n

Review URL: https://codereview.chromium.org/1865833002

Cr-Commit-Position: refs/heads/master@{#35283}