<Swing Dev> RFR: 8169954 JFileChooser/8021253: java.lang.RuntimeException: Default button is not pressed

[Prasanta Sadhukhan]

Please review a test fix for an issue seen to be failing on mach5 systems due to timing issue.
Added setAutoDelay and moved the frame to center of screen which seems to work in mach5 systems for all platforms.
Mach5 job has been run for several iterations in all platforms. Link in JBS.

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Commit messages:
 - 8169954: JFileChooser/8021253: java.lang.RuntimeException: Default button is not pressed

Changes: https://git.openjdk.java.net/jdk/pull/951/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=951&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8169954
  Stats: 33 lines in 2 files changed: 11 ins; 4 del; 18 mod
  Patch: https://git.openjdk.java.net/jdk/pull/951.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/951/head:pull/951

PR: https://git.openjdk.java.net/jdk/pull/951