RFR: 8368498: Use JUnit instead of TestNG for jdk_text tests

[Justin Lu]

Please review this PR which converts all the _TestNG_ based tests under jdk_text to use _JUnit_.

The changes are done in the following order,

- https://github.com/openjdk/jdk/commit/a7840e72269202dfca99d5ce5109bd4f7af0f578: Conversions automated via [script](https://github.com/lahodaj/netbeans/tree/19515c3e2dbc07d977ca227d933197f856121ae5/java/java.openjdk.project/junit-convert).
- https://github.com/openjdk/jdk/commit/2466c5ee970965e57978d8b55b5b7dcad6c2aa6c: Updating to default recommended visibility of test methods + data providers. Cleaning up imports.
- https://github.com/openjdk/jdk/commit/27c439804db61e26d48d7239fd28c99258cb4a9f: Copyright years updated.

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Commit messages:
 - Copyright years
 - Import/visiblity cleanup
 - Automated changes

Changes: https://git.openjdk.org/jdk/pull/27460/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27460&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8368498
  Stats: 569 lines in 21 files changed: 194 ins; 81 del; 294 mod
  Patch: https://git.openjdk.org/jdk/pull/27460.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27460/head:pull/27460

PR: https://git.openjdk.org/jdk/pull/27460