RFR: 8367717: Cleanup atomic_copy64 [v2]

[jonghoonpark]

> related jira issue: https://bugs.openjdk.org/browse/JDK-8367717
> 
> ## Changes
> - deleted all definitions of atomic_copy64
> - replaced all calls to `atomic_copy64` with `AtomicAccess::store(dst, AtomicAccess::load(src))`
> 
> ## Verification
> - Verified by running:
>   - `make run-test TEST="gtest:StubRoutines*"`
>   - `make run-test TEST="gtest:AtomicAccess*"`
> 
> Please let me know if there are any additional or more appropriate verification steps I should perform.

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

  cleanup: align to use AtomicAccess
  
  Signed-off-by: jonghoonpark <dev at jonghoonpark.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27642/files
  - new: https://git.openjdk.org/jdk/pull/27642/files/33a93805..de15f195

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27642&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27642&range=00-01

  Stats: 39 lines in 5 files changed: 3 ins; 26 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/27642.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27642/head:pull/27642

PR: https://git.openjdk.org/jdk/pull/27642