RFR: 8327208: Remove unused method java.util.jar.Manifest.make72Safe

[Eirik Bjørsnøs]

Please review this cleanup PR which suggests we remove the package-private, unused and deprecated method `java.util.jar.Manifest.make72Safe`.

This method was marked deprecated after a cleanup/refactoring in [JDK-8066619](https://bugs.openjdk.org/browse/JDK-8066619) caused it to fall out of use. It should rather be removed.

Some tests reference the `make72Safe` methods in comment, or implement the legacy versions of the same logic to simulate pre JDK 11 line break behavior of `Manifest.write`. These comments and method names are adjusted to not reference the now removed method.

This change was initially discussed here: https://mail.openjdk.org/pipermail/core-libs-dev/2024-February/119819.html

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Commit messages:
 - Update copyright years
 - Remove the internal, unused method Manifest.make72Safe. Update tests to not reference this legacy method.

Changes: https://git.openjdk.org/jdk/pull/18104/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18104&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327208
  Stats: 33 lines in 3 files changed: 2 ins; 21 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/18104.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18104/head:pull/18104

PR: https://git.openjdk.org/jdk/pull/18104