[lworld] RFR: 8279906: [lworld] Javac tolerates synchronized methods in value/primitive records

[Jesper Steen Møller]

Fix JDK-8279906 by masking the record-specific flags.

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Commit messages:
 - 8279906: [lworld] Javac tolerates synchronized methods in value/primitive records

Changes: https://git.openjdk.java.net/valhalla/pull/607/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=607&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8279906
  Stats: 18 lines in 5 files changed: 14 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/607.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/607/head:pull/607

PR: https://git.openjdk.java.net/valhalla/pull/607