RFR: 8353225: Add a way to iterate Klass inside the loaded CDS archive

[Thomas Stuefe]

Please consider.

This patch adds a way to iterate all Klass structures in the loaded CDS archive (`SystemDictionaryShared::iterate_klasses_in_shared_archive(ConstKlassClosure* klassClosure, bool is_static);`). This uses the same mechanism that `PrintSharedArchiveAndExit` uses. I  need this mechanism for some future GC work.

Then, it re-implements `PrintSharedArchiveAndExit` to reuse the new iteration API instead. This also serves as a way to test, since there are pre-existing tests for this flag.

It also adds a new, rather basic, gtest.

Finally, the new gtest picked up a small pre-existing bug in the implementation of `PrintSharedArchiveAndExit`: it prints all array classes of all InstanceKlass inside the archive, for all dimensions, without testing if that array class is part of the archive. The array class may have been created dynamically, however. The patch fixes that.

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Testing:
- I ensured that the output of `PrintSharedArchiveAndExit`, before and after this patch, are identical apart from the small error fix concerning array classes
- I ran all runtime/cds tests on Linux x64
- GHAs

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Commit messages:
 - iterate_klasses

Changes: https://git.openjdk.org/jdk/pull/24311/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24311&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353225
  Stats: 195 lines in 10 files changed: 146 ins; 16 del; 33 mod
  Patch: https://git.openjdk.org/jdk/pull/24311.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24311/head:pull/24311

PR: https://git.openjdk.org/jdk/pull/24311