RFR: 8344882: (bf) Temporary direct buffers should not count against the upper limit on direct buffer memory

[Brian Burkhalter]

Make the memory used by internal temporary direct buffers not count towards the upper limit on direct buffer memory.

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Commit messages:
 - 8344882: (bf) Temporary direct buffers should not count against the upper limit on direct buffer memory

Changes: https://git.openjdk.org/jdk/pull/22339/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22339&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344882
  Stats: 43 lines in 5 files changed: 28 ins; 3 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/22339.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22339/head:pull/22339

PR: https://git.openjdk.org/jdk/pull/22339