[crac] RFR: Collect CREngine child

[Anton Kozlov]

On Thu, 7 Apr 2022 14:02:39 GMT, Anton Kozlov <akozlov at openjdk.org> wrote:

> When VM calls for CREngine it does not properly awaits termination of the engine. In case of `criuengine`, this could lead for a dangling process in the CRIU image [1]. This patch adds missing waitpid that eliminates the problem.
> 
> [1] https://github.com/openjdk/crac/blob/crac/src/java.base/unix/native/criuengine/criuengine.c#L68

Ping? This a bit annoying problem that we checkpoint/restore an unnecessary process.

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PR: https://git.openjdk.java.net/crac/pull/18