RFR: JDK-8057606 - Expected UnavailableDeviceException is not thrown when again openning SPI in EXCLUSIVE mode

[alexey karaksin]

issue: https://bugs.openjdk.java.net/browse/JDK-8057606
webrev: http://cr.openjdk.java.net/~alkonsta/8057606/


Hi All,
please review the changes for checking if a device has already been opened.

check inside the same process: devices store in the list
check across processes: check if flock is set.