[15] RFR(XS) 8236681: Shenandoah: Disable concurrent class unloading flag if no class unloading for the GC cycle

[Roman Kennke]

Ok.

Thanks!
Roman

Roman


> Please review this small patch that disables concurrent class unloading
> if there is no class unloading for the particular GC cycle.
> 
> This is not a fatal error, but can confuse verifier.
> 
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8236681
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8236681/webrev.00/
> Test:
>   hotspot_gc_shenandoah (fastdebug and release)
> 
> 
> Thanks,
> 
> -Zhengyu
>