RFR: Update jextract to reflect latest API tweaks

[Maurizio Cimadamore]

We have done a number of smaller changes to the FFM API which require a refresh in the jextract code:

* Move `ValueLayout.OfAddress` to standalone class (`AddressLayout`)
* Tweak `MemorySegment::reinterpret` to accept `Arena` instead of `MemorySegment.Scope`
* Removal of `MemoryLayout::valueLayout` factory.

This patch fixes jextract to deal with these changes.

-------------

Commit messages:
 - Initial push

Changes: https://git.openjdk.org/jextract/pull/111/files
 Webrev: https://webrevs.openjdk.org/?repo=jextract&pr=111&range=00
  Stats: 46 lines in 19 files changed: 24 ins; 1 del; 21 mod
  Patch: https://git.openjdk.org/jextract/pull/111.diff
  Fetch: git fetch https://git.openjdk.org/jextract pull/111/head:pull/111

PR: https://git.openjdk.org/jextract/pull/111