<i18n dev> RFR: 8374433: java/util/Locale/PreserveTagCase.java does not run any tests

[Naoto Sato]

Removing `static` from the JUnit test cases so that they are executed

-------------

Commit messages:
 - initial commit

Changes: https://git.openjdk.org/jdk/pull/29021/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29021&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8374433
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/29021.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29021/head:pull/29021

PR: https://git.openjdk.org/jdk/pull/29021