RFR: 8309870: Using -proc:full should be considered requesting explicit annotation processing

[Joe Darcy]

Minor fix to new-in-JDK-21 functionality.

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Commit messages:
 - Backport 3ce1240ca1b4139980444c171e317f4bfeff9314

Changes: https://git.openjdk.org/jdk21/pull/10/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21&pr=10&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309870
  Stats: 10 lines in 2 files changed: 8 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk21/pull/10.diff
  Fetch: git fetch https://git.openjdk.org/jdk21.git pull/10/head:pull/10

PR: https://git.openjdk.org/jdk21/pull/10