RFR: 7403: Fix JFR Parser struct types hashcode

[Marcus Hirt]

7403: Fix JFR Parser struct types hashcode

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Commit messages:
 - Formatting
 - 7403: Fix hashcode

Changes: https://git.openjdk.java.net/jmc/pull/313/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=313&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-7403
  Stats: 17 lines in 2 files changed: 11 ins; 3 del; 3 mod
  Patch: https://git.openjdk.java.net/jmc/pull/313.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/313/head:pull/313

PR: https://git.openjdk.java.net/jmc/pull/313