[jdk25u] RFR: 8367689: Revert removal of several compilation-related vmStructs fields

[Francesco Andreuzzi]

Clean backport, reverts the removal of two CI fields which may be used by external tools. Low risk and small change.

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Commit messages:
 - Backport 4c5e901c96dee3885e1b29a53d3400174f9bba09

Changes: https://git.openjdk.org/jdk25u/pull/212/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u&pr=212&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367689
  Stats: 15 lines in 2 files changed: 15 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk25u/pull/212.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u.git pull/212/head:pull/212

PR: https://git.openjdk.org/jdk25u/pull/212