<Swing Dev> RFR: 8255989: Remove explicitly unascribed authorship from Java source files

[Pavel Rappo]

This PR proposes to remove
1. JavaDoc `@author` tags with unclear semantics: `@author unascribed|unattributed|unknown`
2. A couple of astray Form Feed (a.k.a. FF, `\f`,  `0xC`, or `^L`) characters

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.java.net/jdk/pull/1100/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1100&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255989
  Stats: 140 lines in 77 files changed: 0 ins; 80 del; 60 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1100.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1100/head:pull/1100

PR: https://git.openjdk.java.net/jdk/pull/1100