RFR: 8275821: Optimize random number generators developed in JDK-8248862 using Math.unsignedMultiplyHigh() [v4]

[Vamsi Parasa]

> This change optimizes random number generators using Math.unsignedMultiplyHigh()

Vamsi Parasa has updated the pull request incrementally with one additional commit since the last revision:

  add seeds for the random generators to eliminate run-to-run variance

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6206/files
  - new: https://git.openjdk.java.net/jdk/pull/6206/files/8bde4731..78a45142

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6206&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6206&range=02-03

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6206.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6206/head:pull/6206

PR: https://git.openjdk.java.net/jdk/pull/6206