RFR(M): 8223051: support loops with long (64b) trip counts

[Vladimir Ivanov]

> So it's possible that we end up with a loop that doesn't have a
> safepoint but the loop has a call that dominates the exit test and we
> could use its jvm state but it seems like a rare corner case so I don't
> think the extra complexity is worth it. We could revisit this if it
> turns out to be a common enough code pattern.

Sounds good.

Thanks for the clarifications and additional experiments!

Best regards,
Vladimir Ivanov