[foreign-memaccess+abi] RFR: API refresh - part two [v4]

[Maurizio Cimadamore]

> After playing a bit more with the new API changes, I realized there were issues with some of the solutions proposed in [1].
> I will add more details in a separate comment, to keep the header of this PR compact.
> 
> [1] - https://git.openjdk.java.net/panama-foreign/pull/576

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

 - Update src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/SegmentAllocator.java
   
   Co-authored-by: Paul Sandoz <paul.d.sandoz at googlemail.com>
 - Update src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/ResourceScope.java
   
   Co-authored-by: Paul Sandoz <paul.d.sandoz at googlemail.com>
 - Update src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/ResourceScope.java
   
   Co-authored-by: Paul Sandoz <paul.d.sandoz at googlemail.com>
 - Update src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/ResourceScope.java
   
   Co-authored-by: Paul Sandoz <paul.d.sandoz at googlemail.com>
 - Update src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/ResourceScope.java
   
   Co-authored-by: Paul Sandoz <paul.d.sandoz at googlemail.com>
 - Update src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/package-info.java
   
   Co-authored-by: Paul Sandoz <paul.d.sandoz at googlemail.com>
 - Update src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/MemorySegment.java
   
   Co-authored-by: Paul Sandoz <paul.d.sandoz at googlemail.com>

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

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/591/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/591/files/97e6b59e..f3b45ccc

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=591&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=591&range=02-03

  Stats: 7 lines in 4 files changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/591.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/591/head:pull/591

PR: https://git.openjdk.java.net/panama-foreign/pull/591