RFR: 8349932: PSPrinterJob sometimes generates unnecessary PostScript commands

[Daniel Gredler]

Trying to print text which is ignored (e.g. `\r` or `\n` or `\t`), or trying to print empty shapes generates PostScript graphics context setup commands which are not necessary. This can lead to unnecessarily large PostScript files, and can complicate analysis / comparison of these files.

Two methods are impacted:

`PSPrinterJob.textOut(...)`: The `prepDrawing()` method should only be called once all sanity checks have passed. Otherwise, it will add PS graphics context setup commands that may not be necessary.

`PSPrinterJob.deviceFill(...)`: This method should do nothing if the provided `PathIterator` is empty. Otherwise, it will add PS graphics context setup commands that are not necessary.

The changes in `PSPrinterJob.textOut(...)` eliminated a big `if` statement, therefore include some indentation changes. Checking the diff with whitespace ignored should be helpful here.

A test case is included.

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Commit messages:
 - Avoid generation of unnecessary PS commands during printing

Changes: https://git.openjdk.org/jdk/pull/23595/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23595&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349932
  Stats: 312 lines in 2 files changed: 207 ins; 69 del; 36 mod
  Patch: https://git.openjdk.org/jdk/pull/23595.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23595/head:pull/23595

PR: https://git.openjdk.org/jdk/pull/23595