[sealed-types] RFR: Adding permitted classes into declaration references; seems final wil…

[Jan Lahoda]

…l need to be allowed?

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Commit messages:
 - Adding permitted classes into declaration references; seems final will need to be allowed?

Changes: https://git.openjdk.java.net/amber/pull/21/files
 Webrev: https://webrevs.openjdk.java.net/amber/21/webrev.00
  Stats: 74 lines in 4 files changed: 69 ins; 1 del; 4 mod
  Patch: https://git.openjdk.java.net/amber/pull/21.diff
  Fetch: git fetch https://git.openjdk.java.net/amber pull/21/head:pull/21

PR: https://git.openjdk.java.net/amber/pull/21