RFR: 8295298: Automate javax/swing/JFileChooser/FileViewNPETest.java

[Alexey Ivanov]

The automated test follows the instructions of the manual test that was added in #10485.

Instead of selecting the parent folder from the **Look in** combo box, it calls `setCurrentDirectory` directly with the parent of the path which is not traversable. Thus, the current directory of the file chooser is set to `null`.

As the second step, the test finds the combo box and re-selects the currently selected element. Without the fix for [JDK-6616245](https://bugs.openjdk.org/browse/JDK-6616245), `NullPointerException` is thrown and the test fails; with the fix applied, the original folder is selected and the test passes.

@mrserb and @TejeshR13, please, take a look.

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Commit messages:
 - 8295298: Automate javax/swing/JFileChooser/FileViewNPETest.java

Changes: https://git.openjdk.org/jdk/pull/10801/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10801&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295298
  Stats: 99 lines in 1 file changed: 53 ins; 23 del; 23 mod
  Patch: https://git.openjdk.org/jdk/pull/10801.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10801/head:pull/10801

PR: https://git.openjdk.org/jdk/pull/10801