Remove ArrayUtil.timSort? [LUCENE-7268]

Is there some workload where our timSort is better than the JDK one? Should we just remove ours if its slower?

Not that its a great test, but i switched Polygon2D edge sorting (just the one where it says "sort the edges then build a balanced tree from them") from Arrays.sort to ArrayUtil.timSort and was surprised when performance was much slower for an enormous polygon (http://people.apache.org/\~mikemccand/geobench/cleveland.poly.txt.gz)

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Migrated from [LUCENE-7268](https://issues.apache.org/jira/browse/LUCENE-7268) by Robert Muir (@rmuir), updated May 02 2016
Attachments: [LUCENE-7268_mods.patch](https://apache.github.io/lucene-jira-archive/attachments/LUCENE-7268/LUCENE-7268_mods.patch)

Start with ArrayUtil.timSort and the Polygon2D edge-sorting call site mentioned in the issue; compare it with Arrays.sort using the linked Cleveland polygon workload. Review LUCENE-7268_mods.patch and the existing comments, then make a benchmark-backed decision on whether the custom sort should remain or be removed.

Written by the indexing model from the issue text.