[lworld] RFR: 8331496: [lworld] Class::isValue, Class::isIdentity and new java.lang.reflect APIs should be reflective preview API

[Mandy Chung]

Mark the reflection APIs added for JEP 401 as reflective preview API.

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Commit messages:
 - 8331496: [lworld] Class::isValue, Class::isIdentity and new java.lang.reflect APIs should be reflective preview API

Changes: https://git.openjdk.org/valhalla/pull/1090/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1090&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331496
  Stats: 30 lines in 4 files changed: 10 ins; 13 del; 7 mod
  Patch: https://git.openjdk.org/valhalla/pull/1090.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1090/head:pull/1090

PR: https://git.openjdk.org/valhalla/pull/1090