RFR: 8241562: Rework nest host resolution/validation error support

[Lois Foltan]

I've been following the preliminary conversations on this.  I think it 
looks good!
Lois

On 3/26/2020 5:19 AM, David Holmes wrote:
> webrev: http://cr.openjdk.java.net/~dholmes/8241562/webrev/
>
> This is (hopefully) the last pre-integration cleanup for JEP-371: 
> Hidden classes.
>
> Rather than store the error message in a field of InstanceKlass we 
> piggy-back onto the existing ResolutionErrorTable logic and add a new 
> field to the ResolutionErrorEntry.
>
> Also factored out the complex error message logic in linkResolver 
> methods.
>
> There's one code path in free_entry not covered by any existing 
> testing so I will look at developing a test for that. Otherwise all 
> new code paths have been tested.
>
> Thanks,
> David