RFR: 8359472: JVM crashes when attaching a dynamic agent before JVMTI_PHASE_LIVE [v17]

[Francesco Andreuzzi]

> In this PR I add a check to prevent debug builds to crash when an agent tries to attach while the JVM is not in live phase.
> 
> Passes tier1 and tier2 (fastdebug).

Francesco Andreuzzi 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 40 additional commits since the last revision:

 - rename
 - Merge branch 'master' into JDK-8359472
 - return value
 - cc
 - empty stderr
 - jvmti errors
 - indent
 - close
 - rephrase
 - PidJcmdExecutor. unused import. cc
 - ... and 30 more: https://git.openjdk.org/jdk/compare/4ae824a9...1dafec32

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27766/files
  - new: https://git.openjdk.org/jdk/pull/27766/files/ba3dc024..1dafec32

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27766&range=16
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27766&range=15-16

  Stats: 28747 lines in 729 files changed: 16521 ins; 8454 del; 3772 mod
  Patch: https://git.openjdk.org/jdk/pull/27766.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27766/head:pull/27766

PR: https://git.openjdk.org/jdk/pull/27766