Trivial MacOS compiler warning

[Lennart Börjeson]

Forget to tell you that the destructor patch, too, fixed my warning on MacOS.

Best regards,

/Lennart

> 1 feb. 2018 kl. 11:51 skrev Aleksey Shipilev <shade at redhat.com>:
> 
> On 02/01/2018 11:22 AM, Lennart Börjeson wrote:
>> That patch fixed both problems, thank you!
>> 
>> I now see one more warning which seems to be in Shenandoah:
>> 
>> /Users/lennartb/RaT/openJDK/shenandoah-jdk10/src/hotspot/share/gc/shenandoah/shenandoahStringDedup.cpp:157:5: warning: delete called on 'ShenandoahStrDedupTableCleanupTask' that is abstract but has non-virtual destructor [-Wdelete-non-virtual-dtor]
>>    delete _dedup_table_cleanup_task;
>>    ^
>> 1 warning generated.
> 
> OK, looks like we want ShenandoahStrDedupTableCleanupTask destructor to be virtual, even though
> there are no destructors in any subclass of it:
> http://cr.openjdk.java.net/~shade/shenandoah/build/macos-1/webrev.03/
> 
> -Aleksey
>