RFR: 8265208: [JEP-356] : SplittableRandom and SplittableGenerators - splits() methods does not throw NullPointerException when source is null [v2]

[Jim Laskey]

> Add check for null.

Jim Laskey has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:

 - Merge branch 'master' into 8265208
 - Check for null source
 - Make makeXXXSpliterator final
 - Move makeXXXSpilterator from public (@hidden) to protected. No API change.

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Changes: https://git.openjdk.java.net/jdk/pull/3495/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3495&range=01
  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3495.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3495/head:pull/3495

PR: https://git.openjdk.java.net/jdk/pull/3495