RFR: 8331514: Tests should not use the "Classpath" exception form of the legal header

[Jaikiran Pai]

Can I please get a review of this copyright text only change which removes the "Classpath" exception from the `test/jdk/java/lang/ProcessBuilder/JspawnhelperWarnings.java` test file and thus addresses https://bugs.openjdk.org/browse/JDK-8331514?

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Commit messages:
 - 8331514: Tests should not use the Classpath exception form of the legal header

Changes: https://git.openjdk.org/jdk/pull/19046/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19046&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331514
  Stats: 3 lines in 1 file changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/19046.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19046/head:pull/19046

PR: https://git.openjdk.org/jdk/pull/19046