RFR: 8287809: Revisit implementation of memory session [v4]

[Maurizio Cimadamore]

> This is a JDK 19 clone of: https://urldefense.com/v3/__https://github.com/openjdk/jdk/pull/9017__;!!ACWV5N9M2RV99hQ!O0RMiXCfvvDMuk4o6Mu6hube9mx5i9_u0CYjkqbgv6KQ6WfACrLIw7CQsGxgsQ7a_mtUrB9g1kswTncfr3dCb614$ 

Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:

  Revert implicit vs. heap session changes

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

Changes:
  - all: https://git.openjdk.org/jdk19/pull/22/files
  - new: https://git.openjdk.org/jdk19/pull/22/files/b605aeab..a6841b24

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk19&pr=22&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk19&pr=22&range=02-03

  Stats: 14 lines in 5 files changed: 4 ins; 3 del; 7 mod
  Patch: https://git.openjdk.org/jdk19/pull/22.diff
  Fetch: git fetch https://git.openjdk.org/jdk19 pull/22/head:pull/22

PR: https://git.openjdk.org/jdk19/pull/22