[foreign-jextract] RFR: 8249810: Jextract should generate parameter types with Addressable type

[Maurizio Cimadamore]

This patch tweaks jextract so that all foreign functions wrappers use the new Addressable carrier type, as opposed to
the more specific MemoryAddress type. This is useful, as now clients can call such functions with either an address or
a segment, w/o any need to call `MemorySegment::address`.

The bulk of the changes are in the TypeTranslator visitor, which now has a parameter which says as to whether an
addressable should be used. There are also some changes in the HeaderBuilder class, as we now need to call
`Addressable::address' on any incoming addressable parameter (since the method handle generated by the linker expects a
`MemoryAddress`).

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Commit messages:
 - Add support for Addressable carrier

Changes: https://git.openjdk.java.net/panama-foreign/pull/257/files
 Webrev: https://webrevs.openjdk.java.net/panama-foreign/257/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8249810
  Stats: 53 lines in 8 files changed: 13 ins; 2 del; 38 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/257.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/257/head:pull/257

PR: https://git.openjdk.java.net/panama-foreign/pull/257