RFR: 8376666: Convert various BlockOffsetTables to use Atomic<T>

[Thomas Schatzl]

Hi all,

  please review this conversion of the various block offset tables to use `Atomic<T>`. Since they are very similar, and mostly changes from `uint8*` to `Atomic<uint8>*` I merged the conversion together.

It is not the goal to actually merge them into one class that all three collectors use. I filed https://bugs.openjdk.org/browse/JDK-8376667 though, not finding a pre-existing RFE.

Testing: tier1-5, gha

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Commit messages:
 - 8376666

Changes: https://git.openjdk.org/jdk/pull/29482/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29482&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8376666
  Stats: 111 lines in 10 files changed: 7 ins; 5 del; 99 mod
  Patch: https://git.openjdk.org/jdk/pull/29482.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29482/head:pull/29482

PR: https://git.openjdk.org/jdk/pull/29482