[crac] RFR: Active cleanup by CleanerImpl on checkpoint [v6]

[Anton Kozlov]

On Thu, 8 Jun 2023 08:35:34 GMT, Radim Vansa <duke at openjdk.org> wrote:

>> Rather than registering PhantomCleanableRef as a resource that gets cleaned up in the C/R thread force cleanup in the CleanerImpl as this already keeps a list of all eligible references.
>
> Radim Vansa has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove cleanupComplete, handle thread termination

LGTM, thank you!

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

Marked as reviewed by akozlov (Lead).

PR Review: https://git.openjdk.org/crac/pull/73#pullrequestreview-1469688133