RFR: 8369734: JvmtiExport::post_class_file_load_hook return value is never used [v2]

[Francesco Andreuzzi]

> `JvmtiExport::post_class_file_load_hook` returns a boolean, which tells whether the hook modified the class data or not. Users of the function write the same check on their own. I propose replacing the handwritten check with the boolean returned by `post_class_file_load_hook`.
> 
> 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 four additional commits since the last revision:

 - remove dead code
 - revert
 - Merge branch 'master' into JDK-8369734
 - use

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27777/files
  - new: https://git.openjdk.org/jdk/pull/27777/files/ad416a98..8fbf7599

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27777&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27777&range=00-01

  Stats: 5110 lines in 177 files changed: 1555 ins; 3254 del; 301 mod
  Patch: https://git.openjdk.org/jdk/pull/27777.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27777/head:pull/27777

PR: https://git.openjdk.org/jdk/pull/27777