RFR: 7904029: jcstress: Explicitly enable annotation processors to fix build artifacts on JDK 23+

[Pavel Rappo]

In addition to fixing the annotation processing, I also fixed a few "dangling doc comment" warnings I missed earlier in #162. These comments cause build failure on their own.

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jcstress/pull/164/files
  Webrev: https://webrevs.openjdk.org/?repo=jcstress&pr=164&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7904029
  Stats: 32 lines in 5 files changed: 6 ins; 24 del; 2 mod
  Patch: https://git.openjdk.org/jcstress/pull/164.diff
  Fetch: git fetch https://git.openjdk.org/jcstress.git pull/164/head:pull/164

PR: https://git.openjdk.org/jcstress/pull/164