RFR: 8333647: C2 SuperWord: some additional PopulateIndex tests

[Vladimir Kozlov]

On Wed, 5 Jun 2024 13:06:10 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

> When I did the deep refactoring in https://github.com/openjdk/jdk/pull/19261, I wanted some more tests for `PopulateIndex`. I push them separately to keep the other RFE smaller.
> 
> I filed a follow-up RFE for some cases that do not vectorize: https://bugs.openjdk.org/browse/JDK-8332878

Add Oracle's copyright line to these files.

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Changes requested by kvn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/19558#pullrequestreview-2099739346