RFR: 8301005: Clean up Copy::conjoint_*_atomic on windows

[Erik Österlund]

The atomic copying code on windows has some logic that has been copy pasted for a bunch of types with the only difference being the type. Unfortunately, the jlong copying is using oop copying (even though the values are not at all oops), which isn't super nice. Moreover, this copy pasted sequence isn't actually using Atomic, even though it's for atomic copying, which also isn't super nice. This needs a cleanup, and this patch aims to fix that.

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Commit messages:
 - 8301005: Copy::conjoint_*_atomic on windows

Changes: https://git.openjdk.org/jdk/pull/12197/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12197&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301005
  Stats: 38 lines in 1 file changed: 6 ins; 26 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/12197.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12197/head:pull/12197

PR: https://git.openjdk.org/jdk/pull/12197