RFR: 8329320: Simplify awt/print/PageFormat/NullPaper.java test

[Alexey Ivanov]

Remove all the leftovers of the _"standard instructions" machinery_ from the `NullPaper.java` test.

The test code consists of two lines now: concise and clear.

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Commit messages:
 - Remove redudant comment; add blank line
 - 8329320: Simplify awt/print/PageFormat/NullPaper.java test

Changes: https://git.openjdk.org/jdk/pull/18547/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18547&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8329320
  Stats: 177 lines in 1 file changed: 6 ins; 155 del; 16 mod
  Patch: https://git.openjdk.org/jdk/pull/18547.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18547/head:pull/18547

PR: https://git.openjdk.org/jdk/pull/18547