EnsoMultiValue.firstDispatch to speed benchmarks up

[JaroslavTulach]

Pull Request Description

Even more speed up for benchmarks introduced by #11846. Avoids cloning of array in reorderOnly situation at the expense of additional int field in each EnsoMultiValue object.

Important Notes

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• All code follows the
  Java,
• Unit tests continue to pass
• Benchmarks are faster over Initial benchmarks for intersection types + a bit of speedup #11924
  • first benchmark run
  • second benchmark run

[JaroslavTulach]

The idea behind this PR's speed up is to avoid mv.values.clone() when we only need to select new single pivot value. Instead we give each EnsoMultiValue a firstDispatch index into the array that identifies the location of the currently selected type. Then ths reorderOnly operation can share the same mv.values array with the new EnsoMultiValue.

[JaroslavTulach]

Benchmarks results. Twice as fast:

Twice as fast:

Remains the same:

Remains the same:

[Akirathan]

I like the speedup and the number of asserts in EnsoMultiValue.