RFR: Update jextract to reflect latest API changes

Fri Feb 10 17:46:48 UTC 2023

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.

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Commit messages:
 - Polish test
 - Drop spurious changes
 - Fix test
 - Use target layouts for pointers
 - Add support for latest API changes

Changes: https://git.openjdk.org/jextract/pull/102/files
 Webrev: https://webrevs.openjdk.org/?repo=jextract&pr=102&range=00
  Stats: 238 lines in 47 files changed: 91 ins; 24 del; 123 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