[foreign-jextract] RFR: 8253823: Investigate ways to make handoff-like operation more explicit (foreign-jextract edition) [v2]

[Maurizio Cimadamore]

> This patch replaces all references to `withOwnerThread(null)` with the new `share()`.

Maurizio Cimadamore has updated the pull request incrementally with three additional commits since the last revision:

 - Merge against latest changes
 - Merge branch 'foreign-abi' into rebuilder-segments+jextract
 - 8253823: Investigate ways to make handoff-like operation more explicit
   
   Reviewed-by: psandoz, jvernee

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

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/366/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/366/files/4f6a1b79..8e8e2447

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=366&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=366&range=00-01

  Stats: 128 lines in 11 files changed: 45 ins; 54 del; 29 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/366.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/366/head:pull/366

PR: https://git.openjdk.java.net/panama-foreign/pull/366