[foreign-jextract] RFR: 8254682: Close MemorySegments passed to upcalls after the upcall is done

[Jorn Vernee]

These are the jextract fixes needed after: https://github.com/openjdk/panama-foreign/pull/379

For concise diff, see: https://github.com/openjdk/panama-foreign/commit/972daf1f898c1e85e2a2d8b43433bf90f37d7e97

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Commit messages:
 - Copy MemorySegment leaked from upcall
 - Merge branch 'Close_Segments' of H:\cygwin64\home\Jorn\cygwin-projects-new\foreign-abi into foreign-jextract
 - Close segments passed to upcalls after passing

Changes: https://git.openjdk.java.net/panama-foreign/pull/380/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=380&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8254682
  Stats: 59 lines in 8 files changed: 35 ins; 7 del; 17 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/380.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/380/head:pull/380

PR: https://git.openjdk.java.net/panama-foreign/pull/380