[foreign-preview] RFR: 8281855: Rename ResourceScope to MemorySession [v7]

[Maurizio Cimadamore]

> This patch implements some of the changes described in [1] and [2]. More specifically, the `ResourceScope` abstraction is renamed into `MemorySession`, and the session accessors in `MemorySegment`, `NativeSymbol` and `VaList` are tweaked to return *non-closeable* session views. To counteract this change, `MemorySession` now supports `equals` and `hashCode`, so that sessions views can be compared to each other in ways that are not identity-sensitive.
> 
> [1] - https://mail.openjdk.java.net/pipermail/panama-dev/2022-February/016152.html
> [2] - https://mail.openjdk.java.net/pipermail/panama-dev/2022-February/016254.html

Maurizio Cimadamore has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 12 commits:

 - Merge branch 'foreign-preview' into session_preview
 - Fix spurious reference to ResourceScopeImpl after merge
 - Merge branch 'foreign-preview' into session_preview
 - Address review comments
   * replace spurious usages of `scope` in direct buffer template
 - Update src/java.base/share/classes/java/lang/ClassLoader.java
   
   Co-authored-by: Paul Sandoz <paul.d.sandoz at googlemail.com>
 - Update src/java.base/share/classes/java/nio/Direct-X-Buffer.java.template
   
   Co-authored-by: Paul Sandoz <paul.d.sandoz at googlemail.com>
 - Fix more spurious usages of ResourceScope
 - Fix whitespaces
 - Merge branch 'foreign-preview' into session_preview
 - Fix reference to ResourceScope in javadoc
 - ... and 2 more: https://git.openjdk.java.net/panama-foreign/compare/14b6c7b4...bee07da5

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Changes: https://git.openjdk.java.net/panama-foreign/pull/641/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=641&range=06
  Stats: 4693 lines in 139 files changed: 1496 ins; 1328 del; 1869 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/641.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/641/head:pull/641

PR: https://git.openjdk.java.net/panama-foreign/pull/641