RFR: 8307105: JFileChooser InvalidPathException when selecting some system folders on Windows

[Tejesh R]

This is a regression from fix [JDK-8281966](https://bugs.openjdk.org/browse/JDK-8281966): Absolute path of symlink is null in JFileChooser. The fix checks whether the file path is a symbolic link using `Files.isSymbolicLink()` method with path as input. In windows for specific folders like "This PC"/"Network"/"Libraries" the path value will be a hex values which causes InvalidPathException. In order to resolve the issue, since no other checks are available to validate the path of these folders, checking if the file is link firstly and then for symbolic link resolves the problem (since File.isLink() doesn't take path as input rather file is a parameter). Since every symbolic link is a link, this fix seems logical to me.
The fix is tested in CI for regression and is green. The regression fix is also tested for confirmation and works fine.

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Commit messages:
 - Fix + Manual Test

Changes: https://git.openjdk.org/jdk/pull/13998/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13998&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8307105
  Stats: 87 lines in 2 files changed: 84 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/13998.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13998/head:pull/13998

PR: https://git.openjdk.org/jdk/pull/13998