RFR: 8342995: Enhance Attach API to support arbitrary length arguments - Linux [v4]

[Alex Menkov]

> The fix updates Linux (and server-side of macosx) implementation to support Attach API v2 (shared code and Windows implementation were introduced by #20782)
> 
> Testing: tier1,tier2,tier3,tier4,hs-tier5-svc
> manually tested backward compatibility (old tools can attach to current VMs, current tools can attach to older VMs) with jdk21 and jdk8.

Alex Menkov has updated the pull request incrementally with one additional commit since the last revision:

  feedback

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Changes:
  - all: https://git.openjdk.org/jdk/pull/22223/files
  - new: https://git.openjdk.org/jdk/pull/22223/files/27bb3c43..24ab7563

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22223&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22223&range=02-03

  Stats: 3 lines in 2 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/22223.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22223/head:pull/22223

PR: https://git.openjdk.org/jdk/pull/22223