[8] Review request for CR 7077259 [TEST_BUG] [macosx] Test work correctly only when default L&F is Metal.

[Konstantin Shefov]

Hello,

Please review a fix for the issue:
7077259 [TEST_BUG] [macosx] Test work correctly only when default L&F is 
Metal.

Since all three tests:
   javax/swing/plaf/metal/MetalSliderUI/Test6657026.java
   javax/swing/JSpinner/6532833/bug6532833.java
   javax/swing/JSlider/4252173/bug4252173.java
are specific only for Metal LaF, than using of Metal LaF should be 
forced: UIManager.setLookAndFeel(new MetalLookAndFeel());

The webrev is: http://cr.openjdk.java.net/~kshefov/7077259/webrev.00

Thanks,
Konstantin