RFR (S): 8241704: Add test case for unloadable class with nest host error

[Mandy Chung]

Hi David,

The new test looks fine to me.  Thanks for the elaborated comment that 
helps to understand how this test sets up.  (Caveat: I'm not familiar 
with ClassUnloadCommon test library)

Mandy

On 3/30/20 7:01 AM, David Holmes wrote:
> Bug: https://bugs.openjdk.java.net/browse/JDK-8241704
> webrev: http://cr.openjdk.java.net/~dholmes/8241704/webrev/
>
> After JDK-8241562 there is an untested code path in 
> ResolutionErrorTable::free_entry if we can unload a class that had a 
> nest host validation or resolution error. So I took an existing nest 
> host membership test (where the claimed host is in another package) 
> and ran it in a new classloader and then triggered unloading. With a 
> debugging printf enabled this showed the previously unused code path 
> being executed.
>
> Thanks,
> David