RFR: JDK-8266431: Dual-Pivot Quicksort improvements (Radix sort) [v2]

[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:

  optimized radix sort heuristic

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13568/files
  - new: https://git.openjdk.org/jdk/pull/13568/files/246ea875..32551f60

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13568&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13568&range=00-01

  Stats: 48 lines in 1 file changed: 4 ins; 0 del; 44 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