RFR (trivial) 8189794: Assert in InstanceKlass::cast called from Exceptions::new_exceptions

[David Holmes]

Looks good!

Thanks,
David

On 24/10/2017 8:29 AM, coleen.phillimore at oracle.com wrote:
> Summary: Fix call to InstanceKlass::cast to only be after verifying 
> class is non-null.
> 
> Also fixed an unnecessary InstanceKlass::cast found while looking for 
> similar instances of this bug.  I didn't find this same bug anywhere 
> else.  Tested with internal vm.gc.locker tests, and with JPRT which is 
> equivalent to tier1 only faster at the moment.
> 
> open webrev at http://cr.openjdk.java.net/~coleenp/8189794.01/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-8189794
> 
> Thanks,
> Coleen