[PATCH 1/5][_Hashtable] Add benches

[François Dumont]

Now done, thanks for the review.

On 21/12/2023 22:57, Jonathan Wakely wrote:
> On Thu, 23 Nov 2023 at 21:58, François Dumont  wrote:
>> libstdc++: [_Hashtable] Enhance/Add performance benches
> This one is OK for trunk now, thanks.
>