RFR: 8263979: Cleanup duplicate check in Unicode.contains

[Aleksey Shipilev]

SonarCloud reports an easy problem in Unicode.contains:
 Correct one of the identical sub-expressions on both sides of operator "||"

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Commit messages:
 - 8263979: Cleanup duplicate check in Unicode.contains

Changes: https://git.openjdk.java.net/jdk/pull/3122/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3122&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263979
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3122.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3122/head:pull/3122

PR: https://git.openjdk.java.net/jdk/pull/3122