RFR: 8366948: AOT cache creation crashes when iterating training data [v2]

[Igor Veresov]

> I forgot a lock around `CTD::_ci_records`. It also has to respect the snapshotting protocol. Testing is good.

Igor Veresov has updated the pull request incrementally with one additional commit since the last revision:

  Make DepList more defensive against non-MT-safe use

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27461/files
  - new: https://git.openjdk.org/jdk/pull/27461/files/6fc9d856..bb3add97

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27461&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27461&range=00-01

  Stats: 11 lines in 1 file changed: 11 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/27461.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27461/head:pull/27461

PR: https://git.openjdk.org/jdk/pull/27461