Add recipe to simplify JRE version conditions for JUnit 6 migration

Summary

This PR introduces a new recipe MinimumJreConditions that simplifies JUnit Jupiter test conditions based on a minimum JRE version requirement. As part of the JUnit 6 migration path, this recipe helps clean up obsolete JRE version conditions when migrating to a minimum Java version.

What's Changed

New Recipe: MinimumJreConditions

The recipe processes JUnit Jupiter's JRE conditional annotations (@EnabledOnJre, @DisabledOnJre, @EnabledForJreRange, @DisabledForJreRange) and:

• Removes obsolete test methods that are conditionally enabled only for JRE versions older than the minimum
• Simplifies annotations by removing references to older JRE versions from multi-version conditions
• Cleans up annotations that become redundant when only the minimum JRE version remains
• Preserves necessary conditions for JRE versions at or above the minimum requirement

Key Features

1. Supports multiple annotation formats:

   • JRE enum values: JRE.JAVA_8, JRE.JAVA_17, etc. (also the statically imported ones)
   • Value attribute: value = JRE.JAVA_17
   • Version integers: versions = 17 or versions = { 17, 21 }
   • Range attributes: minVersion = 17, maxVersion = 21

2. Handles range conditions:

   • Removes tests enabled only for ranges ending before the minimum JRE
   • Preserves tests for ranges that include or exceed the minimum JRE
   • Removes annotations for disabled ranges that end before the minimum

3. Smart annotation cleanup:

   • Removes annotations when they become redundant (e.g., @EnabledOnJre(JRE.JAVA_17) when 17 is the minimum)
   • Updates multi-version conditions by filtering out obsolete versions
   • Preserves test structure when conditions are still relevant

Integration with JUnit 6 Migration

The recipe has been added to the main JUnit 6 migration recipe with Java 17 as the default minimum version, aligning with JUnit 6's requirements.

Files Changed

• src/main/java/org/openrewrite/java/testing/junit6/MinimumJreConditions.java - Recipe implementation
• src/main/resources/META-INF/rewrite/junit6.yml - Added recipe to JUnit 6 migration
• src/test/java/org/openrewrite/java/testing/junit6/MinimumJreConditionsTest.java - Comprehensive test coverage

Example Transformations

Before

class MyTest {
    @Test
    @EnabledOnJre(JRE.JAVA_8)
    void testOnlyOnJava8() {
        // This test only runs on Java 8
    }
    
    @Test
    @EnabledOnJre(versions = { 11, 17, 21 })
    void testOnMultipleVersions() {
        // This test runs on Java 11, 17, and 21
    }
    
    @Test
    @EnabledForJreRange(min = JRE.JAVA_8, max = JRE.JAVA_11)
    void testOnOldVersions() {
        // This test runs on Java 8-11
    }
}

After (with minimum JRE 17)

class MyTest {
    // testOnlyOnJava8 removed - obsolete for Java 17+
    
    @Test
    @EnabledOnJre(versions = {17, 21})
    void testOnMultipleVersions() {
        // Updated to only include relevant versions
    }
    
    // testOnOldVersions removed - range is entirely below minimum
}

Testing

Comprehensive test coverage includes:

• Parameterized tests for various annotation formats
• Edge cases for range conditions
• Multi-version annotation handling
• Preservation of non-test methods
• Handling of special JRE values (e.g., JRE.OTHER)

Related Issues

This recipe supports the JUnit 6 migration effort by ensuring test suites are properly cleaned up when moving to newer minimum JRE requirements.