RFR: 8280403: RegEx: String.split can fail with NPE in Pattern.CharPredicate::match

[Ian Graves]

Replacing a buggy NPE with a PatternSyntaxException for cases with a bad intersection operator.

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Commit messages:
 - 8280403: RegEx: String.split can fail with NPE in Pattern.CharPredicate::match

Changes: https://git.openjdk.java.net/jdk/pull/7199/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7199&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8280403
  Stats: 11 lines in 2 files changed: 11 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7199.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7199/head:pull/7199

PR: https://git.openjdk.java.net/jdk/pull/7199