[PATCH 1/7] benchtests: Add modff benchtest

[Wilco Dijkstra]

Hi Adhemerval,

> It adds four ranges, which is how the generic implementation handles
> normal numbers:
>
>  1. Random inputs in the range [0.0, 1.0];
>  2. Random inputs in the range [1.0, (float)(1U << 23)];
>  3. Random inputs in the range [(float)(1U << 23), FLT_MAX];
>  4. Random integral inputs in the range [0.0, (float)(1U << 23)].

LGTM

Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>

Cheers,
Wilco