RFR: JDK-8289238: Refactoring changes to PassFailJFrame Test Framework [v4]

[Harshitha Onkar]

> Currently PassFailJFrame.positionTestFrame() and PassFailJFrame.addTestFrame() take Frame as input parameter, this has been changed to Window.
> 
> Refactored the above method names to reflect the functionality & input parameter type -
> addTestWindow(), positionTestWindow()
> 
> Additionally added test fail reason to `forceFail()` to avoid NPE.
> 
> Benefits of the change -
> 
> - Since Window is a parent class, this would allow the test frame to be a Window/Frame/Dialog and not be restricted to a Frame.
> - Code reusability - no need to have separate methods to manage Frame and Window
> - Additionally it would allow proper clean-up of window and its container subclasses which are added to the PassFailJFrame.

Harshitha Onkar has updated the pull request incrementally with one additional commit since the last revision:

  minor change

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/9300/files
  - new: https://git.openjdk.org/jdk/pull/9300/files/1270cafa..3539873f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9300&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9300&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9300.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9300/head:pull/9300

PR: https://git.openjdk.org/jdk/pull/9300