[vectorIntrinsics+compress] RFR: 8274975: Add micro benchmark: ALIBABA selective store use case

[Joshua Zhu]

On Mon, 11 Oct 2021 06:08:27 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Thanks Jatin for your review.
>> This test I added is placed together with other benchmarks extracted from user cases.
>> The mask computation inside the loop is the essential logic in real scenario.
>> We can add micro benchmarks in test/micro/org/openjdk/bench/jdk/incubator/vector/operation and then evaluate performance for compression / expanding in single API level.
>
> Ok got it, thanks! 
> BTW can you also post the AVX2 numbers just to see how does it compare against scalar version when direct compress/expand instructions are not supported by target.

FYI
![image](https://user-images.githubusercontent.com/70769035/136771782-cfb8adcf-7336-4173-a617-e2b89eadb1cb.png)

-------------

PR: https://git.openjdk.java.net/panama-vector/pull/149