[vector] Remove unnecessary node AbsV

[Vladimir Ivanov]

Hi Qi,

> We already have nodes AbsVB/AbsVI/AbsVD/AbsVF/AbsVS/AbsVL for every primitive
> type. These nodes can cover all situations. So AbsV can be removed.
> 
> Please help me review this patch.
> 
> Webrev: http://cr.openjdk.java.net/~qfeng/panama/vectorapi/remove_absv/webrev/

Looks good.

In the longer term, I prefer us to move in the opposite direction: 
replace the family of type-specific nodes per operation with a single 
generic node and during matching rely on vector type info 
(n->bottom_type()->is_vect()) to choose proper implementation.

Best regards,
Vladimir Ivanov