[vector] Partial intrinsification support for with and get

[Lupusoru, Razvan A]

Hello,

I'd like to contribute the infrastructure to be able to intrinsify 'with' (insert) and 'get' (extract). The actual implementation with x86 instructions is coming in a follow up patch from my teammates.
http://cr.openjdk.java.net/~rlupusoru/panama/webrev_getwith_01/index.html

One change I will need to make is make the base class methods as abstract to match Paul's recent changes. I will make sure to do that before merging. In meantime, please take a look to see if you identify any other issues.

Thanks,
Razvan