RFR[T]: 8240133: G1DirtyCardQueue destructor has useless flush

[Kim Barrett]

> On Mar 6, 2020, at 4:10 AM, Stefan Johansson <stefan.johansson at oracle.com> wrote:
> 
> Hi Kim,
> 
> On 2020-03-04 03:17, Kim Barrett wrote:
>> Please review this trivial change to remove the useless call to flush() from
>> the G1DirtyCardQueue destructor.  See the CR for more details.  This removes
>> the need for a non-trivial destructor for that class.
>> CR:
>> https://bugs.openjdk.java.net/browse/JDK-8240133
>> Webrev:
>> https://cr.openjdk.java.net/~kbarrett/8240133/open.00/
> Would it make sense to add an assert into the destructor to ensure no entries were added? Or is that problematic for some reason.

~PtrQueue() already asserts _buf == NULL.

> If you prefer not to, I'm good with this change and you can consider it reviewed.

Thanks.