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

[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.

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Commit messages:
 - attach_v2_linux

Changes: https://git.openjdk.org/jdk/pull/22223/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22223&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342995
  Stats: 323 lines in 5 files changed: 98 ins; 193 del; 32 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