RFR: 8287024: G1: Improve the API boundary between HeapRegionRemSet and G1CardSet [v3]

[Thomas Schatzl]

> Hi all,
> 
>   can I get reviews for this small refactoring that clarifies the boundaries of what kind of data `HeapRegionRemSet` and `G1CardSet` should operate on?
> 
> * `HeapRegionRemSet` deals with addresses, heap regions
> * `G1CardSet` deals with card indexes in the heap, card regions and cards within card regions
> 
> The `G1CardSet::add_card()` and `G1CardSet::contains_card()` methods are fuzzy about that, they require the caller (`HeapRegionRemSet`) to know about card regions and cards within regions. 
> 
> Testing: gha
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - Merge branch 'master' into 8287024-improve-api-boundary
 - ayang review
 - initial version

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Changes: https://git.openjdk.java.net/jdk/pull/8790/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8790&range=02
  Stats: 146 lines in 5 files changed: 81 ins; 53 del; 12 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8790.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8790/head:pull/8790

PR: https://git.openjdk.java.net/jdk/pull/8790