This ensures our optimizing compilers as well as the interpreter are
never tasked with compiling the generator-resuming builtin methods. The
corresponding intrinsics for those methods are not supported and it is
not possible to provide a C++ reference implementation for them. We do
this by assigning builtin function ids to them that we can recognize
during the compiler dispatch.

Note that this also affects the interpreter, because methods having a
builtin function id assigned are not interpreted ({function_data} field
is overlapping). If this ever changes we can still do an early check in
the compiler dispatch (similar to the optimizing compilers) easily.

This applies to the following methods:
- Generator.prototype.next (calls Runtime_GeneratorNext).
- Generator.prototype.return (calls Runtime_GeneratorReturn).
- Generator.prototype.throw (calls Runtime_GeneratorThrow).

R=neis@chromium.org
BUG=v8:4681
LOG=n

Review URL: https://codereview.chromium.org/1779123003

Cr-Commit-Position: refs/heads/master@{#34675}