RFR: 8375983: G1: Convert G1ConcurrentRefineStats to use Atomic<T> [v2]

[Thomas Schatzl]

> Hi all,
> 
>   please review this change that converts `G1ConcurrentRefineStats` to use `Atomic<T>`.
> 
> The only notable thing is that there has been need to expand the assignment in `reset()` since the assignment operator for `Atomic<T>` is not defined, and I did not see it worth adding one.
> 
> Testing: gha
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:

  * move changes to inline.hpp files to reduce line lengths of hpp file
  * adjust includes

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29347/files
  - new: https://git.openjdk.org/jdk/pull/29347/files/1d017660..8b6d3106

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29347&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29347&range=00-01

  Stats: 34 lines in 9 files changed: 3 ins; 4 del; 27 mod
  Patch: https://git.openjdk.org/jdk/pull/29347.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29347/head:pull/29347

PR: https://git.openjdk.org/jdk/pull/29347