[14] RFR (S) 8240948: Shenandoah: cleanup not-forwarded-objects paths after JDK-8240868

[Roman Kennke]

The patch looks good to me.

Thanks,
Roman


> Original RFE:
>   https://bugs.openjdk.java.net/browse/JDK-8240948
>   https://hg.openjdk.java.net/jdk/jdk/rev/61f6c19d1a56
> 
> The context is a bit different in 14.
> 
> 14u webrev:
>   https://cr.openjdk.java.net/~shade/8240948/webrev.14u.01/
> 
> Testing: hotspot_gc_shenandoah
>