RFR: Update jextract to reflect latest API changes [v2]

[Maurizio Cimadamore]

> This patch refreshes the generated bindings to reflect the latest API changes in https://github.com/openjdk/panama-foreign/pull/787.
> 
> The changes are straightforward, and mostly consist in removing `.scope()` calls when creating upcalls, and with replacing some `SegmentScope` parameters with `Arena` ones.

Maurizio Cimadamore has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains seven commits:

 - Merge branch 'panama' into arena_lump
 - Revert spurious changes
 - Polish test
 - Drop spurious changes
 - Fix test
 - Use target layouts for pointers
 - Add support for latest API changes

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Changes: https://git.openjdk.org/jextract/pull/102/files
 Webrev: https://webrevs.openjdk.org/?repo=jextract&pr=102&range=01
  Stats: 102 lines in 34 files changed: 4 ins; 3 del; 95 mod
  Patch: https://git.openjdk.org/jextract/pull/102.diff
  Fetch: git fetch https://git.openjdk.org/jextract pull/102/head:pull/102

PR: https://git.openjdk.org/jextract/pull/102