RFR: 8375436: G1: Convert G1CardSet classes to use Atomic<T>

[Thomas Schatzl]

Hi all,

  please review this removal of use of the AtomicAccess class in G1 card set related classes, replacing with use of Atomic<T>.

Although a bit on the large side, it would be hard to do the card set changes separately per class. Other than that I think it is fairly straightforward, except for the addition of a copy constructor for `G1CardSetHashTableValue` because the `ConcurrentHashTable` requires it.

Testing: gha

Thanks,
  Thomas

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Commit messages:
 - * fix whitespace
 - 8375436

Changes: https://git.openjdk.org/jdk/pull/29274/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29274&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8375436
  Stats: 119 lines in 6 files changed: 9 ins; 4 del; 106 mod
  Patch: https://git.openjdk.org/jdk/pull/29274.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29274/head:pull/29274

PR: https://git.openjdk.org/jdk/pull/29274