[9] Review Request: 8030953 SelectionVisible test should test multiline selection in case of TextArea

[Sergey Bylokhov]

Hello.
Please review the fix for jdk 8.
The test for TextArea was copied from the version of 
TextField(JDK-7150100), but TextArea supports multiline selection it 
would be good to test it to increase coverage.

Bug: https://bugs.openjdk.java.net/browse/JDK-8030953
Webrev can be found at: http://cr.openjdk.java.net/~serb/8030953/webrev.00/

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Best regards, Sergey.