test: migrate 9 setUp/tearDown TestCase files to JUnit 5 (Phase 3)

Targets: files that extend junit.framework.TestCase with setUp and/or
tearDown lifecycle methods, no suite() method, no role as a base class.

Transformations applied per file:
- drop extends TestCase and junit.framework.* imports
- @Override protected void setUp/tearDown -> @BeforeEach/@AfterEach
  with package-private visibility (no @Override)
- add @Test to each public void testXxx method
- add static org.junit.jupiter.api.Assertions imports where bare
  assertEquals/assertTrue/etc were inherited from TestCase

16 @Test methods migrated, 8 @BeforeEach, 5 @AfterEach.
TimeTest dropped a stray junit.framework.Assert qualifier.

Test invocation count unchanged (2702/275/83). Spock untouched.

Part of OpenSpec change migrate-junit5.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>