improve TimeSeries split performance

[samirromdhani]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• A PR or issue has been opened in all impacted repositories (if any)

Does this PR already have an issue describing the problem?

Fixes #1634

What kind of change does this PR introduce?

What is the current behavior?

What is the new behavior (if this is a feature change)?

Does this PR introduce a breaking change or deprecate an API?

• Yes
• No

If yes, please check if the following requirements are fulfilled

• The Breaking Change or Deprecated label has been added
• The migration steps are described in the following section

What changes might users need to make in their application due to this PR? (migration steps)

• The default behavior of the split method was changed to improve performance in both execution time and memory consumption.
• A new method was introduced:toCompactArray, split now uses that.
• toArray still available, users can choose toCompactArray for improved memory usage.

Other information:

powsybl-benchmark way with tsSize = 100000:

Benchmark     Mode  Cnt        Score   Error  Units
splitV0       avgt       3276192,839          us/op       <- split before performance improvement
split         avgt          3236,725          us/op       <- split after performance improvement

splitV0:gc.alloc.rate.norm  avgt       40016480045,333            B/op  <- split before performance improvement
split:gc.alloc.rate.norm    avgt           6801644,438            B/op <- split after performance improvement

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud