RFR: JDK-8266431: Dual-Pivot Quicksort improvements (Radix sort) [v5]

[Laurent Bourgès]

> * Optimized mixed insertion sort
>     * Optimized insertion sort
>     * Optimized Radix sort
>     * Updated microbenchmark
> 
> I am going on previous PR by Vladimir Yaroslavskyi: https://github.com/openjdk/jdk/pull/3938

Laurent Bourgès has updated the pull request incrementally with one additional commit since the last revision:

  improved and more obvious max length test to always respect max heap memory footprint

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13568/files
  - new: https://git.openjdk.org/jdk/pull/13568/files/1d4af827..07771000

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13568&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13568&range=03-04

  Stats: 8 lines in 1 file changed: 2 ins; 1 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/13568.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13568/head:pull/13568

PR: https://git.openjdk.org/jdk/pull/13568