RFR: 7065228: To interpret case-insensitive string locale independently [v2]

[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

Darragh Clarke has updated the pull request incrementally with two additional commits since the last revision:

 - Update src/java.base/share/classes/sun/net/www/protocol/http/DigestAuthentication.java
   
   Co-authored-by: Daniel Jelinski <djelinski1 at gmail.com>
 - removed StreamTokenizer changes, will make seperate ticket for those

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Changes:
  - all: https://git.openjdk.org/jdk/pull/14006/files
  - new: https://git.openjdk.org/jdk/pull/14006/files/a79969c2..6d40e1c8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14006&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14006&range=00-01

  Stats: 3 lines in 2 files changed: 0 ins; 1 del; 2 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