RFR: 8293920: G1: Add index based heap region iteration

Fri Sep 16 10:00:42 UTC 2022

On Fri, 16 Sep 2022 09:30:14 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Simple change of introducing a new `iterate` method. It's dead code for now, and will be used soon in [JDK-8293210](https://bugs.openjdk.org/browse/JDK-8293210).
> 
> Test: hotspot_gc

I was hoping that somehow there could be a solution with somewhat less code duplication (but also not overdoing with lots of additional boilerplate to make that possible), but I have no good idea either.
Lgtm.

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Marked as reviewed by tschatzl (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10301