RFR: Weaken assert in Traversal GC

[Aleksey Shipilev]

On 02/21/2018 04:13 PM, Roman Kennke wrote:
> We've seen occasional assert that an object should not be forwarded.
> This may happen when traversal GC has been cancelled. This change
> weakens the assert to account for that.
> 
> http://cr.openjdk.java.net/~rkennke/fixtraversalassert/webrev/
> 
> Ok?

OK

-Aleksey