[8] Review request for CR 8012468: [TEST_BUG] javax/swing/PopupFactory/6276087/NonOpaquePopupMenuTest.java doesn't release mouse button

[vera akulova]

Hello, Please review a fix for the issue:    JDK-8012468: [TEST_BUG] javax/swing/PopupFactory/6276087/NonOpaquePopupMenuTest.java doesn't release mouse button     The webrev is http://cr.openjdk.java.net/~kshefov/8012468/webrev.00/   The fix adds release of pressed mouse button.   Thanks, Vera.