[lworld] RFR: [lworld] Enable all flattening by default

[Chen Liang]

On Wed, 4 Jun 2025 14:37:36 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

> Now that the implementation is sufficiently stable, let's enable all flattening by default. At this point, I think the flags are still useful but we might want to remove/merge them later.
> 
> Thanks,
> Tobias

Do we need to adjust the flags in valhalla tests, at least the compiler ones, such as ones that turn these on, or are there no such test triggers yet?

-------------

PR Comment: https://git.openjdk.org/valhalla/pull/1480#issuecomment-2940881147