Integrated: 8313880: Incorrect copyright header in jdk/java/foreign/TestFree.java after JDK-8310643

[Per Minborg]

This PR fixes a formatting error in a copyright header.

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Commit messages:
 - Restore enablePreview
 - Fix copyright formatting in TestFree

Changes: https://git.openjdk.org/jdk/pull/15175/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15175&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313880
  Stats: 6 lines in 1 file changed: 2 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/15175.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15175/head:pull/15175

PR: https://git.openjdk.org/jdk/pull/15175