RFR: 8257457: Update --release 16 symbol information for JDK 16 build 28

[Joe Darcy]

Update symbol information for --release 16 to JDK 16 b28, includes updates for JEP 390.

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Commit messages:
 - 8257457

Changes: https://git.openjdk.java.net/jdk/pull/1754/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1754&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8257457
  Stats: 235 lines in 4 files changed: 149 ins; 2 del; 84 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1754.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1754/head:pull/1754

PR: https://git.openjdk.java.net/jdk/pull/1754