RFR (XXS): 8192961: Remove some double semicolons

[Langer, Christoph]

Hi,

can I please have a review for this small cleanup. I spotted some double 
semicolons at a few import statements.

Bug: https://bugs.openjdk.java.net/browse/JDK-8192961
Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8192961.0/

Thanks
Christoph