RFR: 8311648: Refactor the Arena/Chunk/ChunkPool interface [v6]

[Johan Sjölen]

> Hi,
> 
> This PR refactors the Arena code without introducing any changes in behavior. I believe that this leads to a much clearer API and that this will in turn simplify the maintenance of this code. `Chunk` is now much more "dumb", mainly acting as a way of interrogating the chunk of data that it is holding. The `ChunkPool` gains a more prominent role, being entirely responsible for the memory allocation strategy used. `Arena` is basically unchanged, as it orchestrates the usage of these two APIs. The `chop` and `next_chop` methods are re-defined to be static inside of `Chunk`, having an object `delete` itself  is very surprising, so I'm happy to get rid of that.
> 
> I hope that you agree with me on these changes!
> 
> Cheers,
> Johan

Johan Sjölen has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 12 additional commits since the last revision:

 - Merge remote-tracking branch 'origin/master' into rework-arena
 - Swap around argument
 - Move stuff around to make diffs smaller
 - Remove comments
 - Hide ChunkPool, make ChunkPoolCleaner be started from Arena
 - One more comment
 - Remove comment sections
 - Missed two small issues
 - Move allocation responsibilities to ChunkPool
 - Remove operator new/delete
 - ... and 2 more: https://git.openjdk.org/jdk/compare/89de4ccc...d8196bab

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14803/files
  - new: https://git.openjdk.org/jdk/pull/14803/files/cc3ad84d..d8196bab

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14803&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14803&range=04-05

  Stats: 86339 lines in 1772 files changed: 23969 ins; 54035 del; 8335 mod
  Patch: https://git.openjdk.org/jdk/pull/14803.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14803/head:pull/14803

PR: https://git.openjdk.org/jdk/pull/14803