RFR: 8267110: Update java.util to use instanceof pattern variable

[Patrick Concannon]

Hi,

Could someone please review my code for updating the code in the `java.util` package to make use of the `instanceof` pattern variable?

Kind regards,
Patrick

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Commit messages:
 - 8267110: Update java.util to use instanceof pattern variable

Changes: https://git.openjdk.java.net/jdk/pull/4088/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4088&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267110
  Stats: 304 lines in 35 files changed: 1 ins; 144 del; 159 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4088.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4088/head:pull/4088

PR: https://git.openjdk.java.net/jdk/pull/4088