RFR: 7065228: To interpret case-insensitive string locale independently

[Darragh Clarke]

Updated instances of `toLowerCase` and `toUpperCase` in several net and io files to specify `Locale.ROOT` to ensure that case conversion issues don't occur,

I didn't add any new tests but ran tier 1-3 with no issues

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Commit messages:
 - added some case conversions missed previously
 - updated copyright year and cleaned up some formatting of imports
 - merged master into branch
 - Specify use of Locale.Root to avoid issues with case conversion

Changes: https://git.openjdk.org/jdk/pull/14006/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14006&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-7065228
  Stats: 76 lines in 21 files changed: 15 ins; 0 del; 61 mod
  Patch: https://git.openjdk.org/jdk/pull/14006.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14006/head:pull/14006

PR: https://git.openjdk.org/jdk/pull/14006