[jdk20] RFR: 8300275: SegmentScope.isAccessibleBy returning incorrect values [v2]

[Maurizio Cimadamore]

> The implementation of MemorySessionImpl::isAccessibleBy is incorrect, and ends up always returning `false` for scopes associated with shared arenas.
> This patch rectifies that, and adds some tests.

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

  Update copyrights

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Changes:
  - all: https://git.openjdk.org/jdk20/pull/110/files
  - new: https://git.openjdk.org/jdk20/pull/110/files/46f5abee..e8fcf2d3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk20&pr=110&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk20&pr=110&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk20/pull/110.diff
  Fetch: git fetch https://git.openjdk.org/jdk20 pull/110/head:pull/110

PR: https://git.openjdk.org/jdk20/pull/110