RFR: 8376350: Convert ReferenceProcessorPhaseTimes to use Atomic<T> [v2]

[Thomas Schatzl]

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

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

 - Apply suggestion from @tschatzl
 - Update src/hotspot/share/gc/shared/referenceProcessorPhaseTimes.cpp
   
   Co-authored-by: Stefan Karlsson <stefan.karlsson at oracle.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29423/files
  - new: https://git.openjdk.org/jdk/pull/29423/files/97b28c38..511204d2

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29423&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29423&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/29423.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29423/head:pull/29423

PR: https://git.openjdk.org/jdk/pull/29423