RFR: 8248862: Implement Enhanced Pseudo-Random Number Generators

[Jim Laskey]

This PR is to introduce a new random number API for the JDK. The primary API is found in RandomGenerator and RandomGeneratorFactory. Further description can be found in the JEP https://openjdk.java.net/jeps/356 .

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Commit messages:
 - 8248862: Implement Enhanced Pseudo-Random Number Generators
 - Merge branch 'master' into 8248862
 - Merge branch 'master' into 8248862
 - 8248862: Implement Enhanced Pseudo-Random Number Generators
 - Merge branch 'master' into 8248862
 - 8248862: Implement Enhanced Pseudo-Random Number Generators
 - 8248862; Implement Enhanced Pseudo-Random Number Generators
 - Merge branch 'master' into 8248862
 - 8248862: Implement Enhanced Pseudo-Random Number Generators
 - Merge branch 'master' into 8248862
 - ... and 27 more: https://git.openjdk.java.net/jdk/compare/9efbb463...7469ca58

Changes: https://git.openjdk.java.net/jdk/pull/1273/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1273&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8248862
  Stats: 14875 lines in 31 files changed: 11094 ins; 3704 del; 77 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1273.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1273/head:pull/1273

PR: https://git.openjdk.java.net/jdk/pull/1273