RFR: 8371965: Convert TaskQueueSuper to use Atomic<T>

[Kim Barrett]

Please review this change to TaskQueueSuper to use Atomic<T> rather than
directly applying AtomicAccess to (sometimes!) volatile members. There was
some sketchy stuff around TaskQueueSuper::Age. This has been cleaned up by
hoisting that class to namespace scope (now called TaskQueueAge) and declaring
a PrimitiveConversion::Translate for it.

Testing: mach5 tier1-5

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Commit messages:
 - convert TaskQueueSuper to use Atomic<T>

Changes: https://git.openjdk.org/jdk/pull/28347/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28347&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8371965
  Stats: 87 lines in 1 file changed: 44 ins; 25 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/28347.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28347/head:pull/28347

PR: https://git.openjdk.org/jdk/pull/28347