[vector] RFR (M): Fix ByteVector/ShortVector.shiftR

[Yang Zhang (Arm Technology China)]

> With the following patch I see vsrl4I_reg_imm being used:
>
>   http://cr.openjdk.java.net/~vlivanov/panama/vector/shiftr/webrev.02/

>The problem was with shared [R|L]ShiftCntV nodes: matcher can't fold them into multiple times unless they are marked as shared.

Thanks very much for your quick fix. I think the issue might be in matcher, but I don't know how to fix.

It looks good to me.
 
Regards,
Yang