RFR: 8267670: Update java.io, java.math, and java.text to use switch expressions

[Patrick Concannon]

Hi,

Could someone please review my code for updating the code in the `java.io`, `java.math`, and `java.text` packages to make use of the switch expressions?

Kind regards,
Patrick

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Commit messages:
 - 8267670: Update java.io, java.math, and java.text to use switch expressions

Changes: https://git.openjdk.java.net/jdk/pull/4182/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4182&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267670
  Stats: 328 lines in 11 files changed: 1 ins; 187 del; 140 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4182.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4182/head:pull/4182

PR: https://git.openjdk.java.net/jdk/pull/4182