RFR: 8372119: Missing copyright header in MinMaxVector

[Galder Zamarreño]

Trivial PR to add missing copyright header in JMH benchmark.

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Commit messages:
 - 8372119: Missing copyright header in MinMaxVector

Changes: https://git.openjdk.org/jdk/pull/28387/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28387&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8372119
  Stats: 23 lines in 1 file changed: 23 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/28387.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28387/head:pull/28387

PR: https://git.openjdk.org/jdk/pull/28387