[vector] Fix build failures

[Paul Sandoz]

+1
Paul.

> On May 10, 2020, at 8:36 PM, Qi Feng <Qi.Feng at arm.com> wrote:
> 
> I have reverted the removal of inline on classify_unsafe_addr. You're 
> right, I did want to be consistent before.
> 
> Also I tried with gcc9.3 after you mentioned it. It built successfully 
> without error. In all the gcc versions I've tried, gcc7 and gcc9 can 
> pass the build, while gcc5 and gcc8 can not.
> 
> Please find below the latest patch:
>   Webrev: 
> http://cr.openjdk.java.net/~qfeng/panama/vectorapi/zero_build/webrev.01/
> 
> Regards,
> Qi