RFR: 8078471: The BACKSPACE key doesn't work with the special options"-client -Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel"

[Abhishek Kumar]

The Backspace key doesn't lead to parent directory of current directory for JFileChooser in GTK LAF. 
Added the lazy input value in `GTKLookandFeel` and fix is working fine.

Implemented a manual test to check BackSpace behavior for all installed LAF in Linux platform.
The test mentioned in [JDK-8078471](https://bugs.openjdk.org/browse/JDK-8078471) `javax/swing/JFileChooser/4150029/bug4150029.html` also working fine with GTK option (-client -Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel).

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Commit messages:
 - Whitespace error fix
 - Backspace changes to parent directory

Changes: https://git.openjdk.org/jdk/pull/11291/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11291&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8078471
  Stats: 146 lines in 2 files changed: 146 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/11291.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11291/head:pull/11291

PR: https://git.openjdk.org/jdk/pull/11291