RFR: 8324998: Add test cases for String.regionMatches comparing Turkic dotted/dotless I with uppercase latin I

[Eirik Bjørsnøs]

Please review this test-only PR which improves test coverage of `String.regionMatches` when comparing the Turkic "dotted I" and "dotless i" characters with their latin cousins. 

The test `CompactStrings/RegionMatches.java` currently includes cases comparing these characters against the lowercase latin "i" character, but not against the corresponding uppercase latin "I" character. It would be good to add test cases for the uppercase I as well.

This was originally found in #12637, which was closed without being integrated. I think this test coverage enhancement is worth rescuing from that PR, where it did prove to catch a regression.

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Commit messages:
 - Update copyright year
 - Add test coverage for regionMatches of Turkic dotted I / dotless i against LATIN CAPITAL LETTER I

Changes: https://git.openjdk.org/jdk/pull/17639/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17639&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8324998
  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/17639.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17639/head:pull/17639

PR: https://git.openjdk.org/jdk/pull/17639