RFR(XXS): 7022200 G1: optimized build broken

[John Cuthbertson]

Hi Everyone,

Can I have a couple of volunteers to review this small change? The 
webrev can be found at 
http://cr.openjdk.java.net/~johnc/7022200/webrev.0/  The function 
G1CollectedHeap::is_in_closed_subset was inadvertently placed in #ifdef 
ASSERT conditional compilation resulting in a link failure in the 
optimized build.

Thanks,

JohnC