RFR: 8375971: G1: Convert G1EvacStats to use Atomic<T> [v2]

[Thomas Schatzl]

> Hi all,
> 
>   please review this change that moves `G1EvacStats` to use `Atomic<T>`.
> 
> Testing: gha
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request incrementally with two additional commits since the last revision:

 - * reformatting, avoid long lines
 - * fix compilation

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29341/files
  - new: https://git.openjdk.org/jdk/pull/29341/files/510601bb..5df23350

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29341&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29341&range=00-01

  Stats: 23 lines in 3 files changed: 15 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/29341.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29341/head:pull/29341

PR: https://git.openjdk.org/jdk/pull/29341