[FEATURE] Migrate Java tests from JUnit 4 to JUnit 5

[wangzhigang1999]

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Describe the feature

Migrate the Java test suites in the following Kyuubi-native modules from JUnit 4 to JUnit 5 (Jupiter):

• kyuubi-rest-client
• kyuubi-util
• kyuubi-hive-jdbc
• externals/kyuubi-data-agent-engine

The vendored Hive beeline tests under kyuubi-hive-beeline/src/test/java/org/apache/hive/beeline/ (package org.apache.hive.beeline) stay on JUnit 4 to remain aligned with upstream Hive and minimize sync friction.

Motivation

• JUnit 4 has been effectively in maintenance mode since 4.13.2 (Feb 2021). Modern test ecosystem (Mockito 5, Testcontainers, Spring Boot 3, etc.) defaults to JUnit 5.
• JUnit 5's @ParameterizedTest removes the @Parameterized runner boilerplate currently used in kyuubi-hive-jdbc (3 files).
• @TempDir parameter injection, assertAll, @Nested, and condition annotations (@EnabledIfSystemProperty, etc.) become available for future tests.
• Our usage is shallow (@Test + @Before/@After + Assert + Parameterized); no @Rule/@ClassRule/Theories, so the migration is mostly mechanical.

Originally suggested in the AGENTS.md review on #7452.

Describe the solution

• Add junit-bom 5.x to root dependencyManagement; keep junit:junit 4.13.2 for the vendored Hive beeline module.
• Switch the four target modules' POMs to org.junit.jupiter:junit-jupiter.
• Mechanical source rewrites:
  • Imports → org.junit.jupiter.api.* / org.junit.jupiter.params.*
  • Annotations: @Before→@BeforeEach, @After→@AfterEach, @BeforeClass→@BeforeAll, @AfterClass→@AfterAll
  • Assert.assertX → Assertions.assertX (with message arg moved to last position)
  • Assume.assumeTrue → Assumptions.assumeTrue
  • @Test(expected = X.class) → assertThrows
  • @RunWith(Parameterized.class) + @Parameters → @ParameterizedTest + @MethodSource / @ValueSource
• Static imports only, no wildcard imports (google-java-format).
• kyuubi-hive-beeline is out of scope — left on JUnit 4 to avoid diverging from upstream Hive's vendored tests.

Additional context

Surfaced during review of #7452:

seems it's time to upgrade to JUnit5 - should be straightforward, as we don't use many JUnit advanced features.

Are you willing to submit PR?

• Yes. I would be willing to submit a PR with guidance from the Kyuubi community to improve.
• No. I cannot submit a PR at this time.