RFR(xs): JDK-8076173: VirtualSpaceNode container_count() and container_count_slow() have different return types

[David Lindholm]

Hi,

Please review this small patch that makes container_count_slow() use the 
same return type as container_count().


Webrev: http://cr.openjdk.java.net/~david/JDK-8076173/webrev.00/
Bug: https://bugs.openjdk.java.net/browse/JDK-8076173

Testing: JPRT.


Thanks,
David