Remove duplicate tests across resolver types and refactor to reduce redundancy

[waveywaves]

Context

In PR #9051, we added comprehensive E2E tests for the shared resolver cache across bundle, git, and cluster resolvers. However, there is significant duplication in test patterns across these resolver types.

Task

Refactor the E2E tests in test/resolver_cache_test.go to reduce redundancy while maintaining coverage.

Current State

The test file contains 15 tests, many of which follow similar patterns:

• TestBundleResolverCache
• TestBundleResolverCacheEviction
• TestBundleResolverCacheTTL
• TestGitResolverCache
• TestGitResolverCacheEviction
• TestGitResolverCacheTTL
• TestClusterResolverCache
• TestClusterResolverCacheEviction
• TestClusterResolverCacheTTL

Proposed Solution

• Extract common test patterns into helper functions
• Consider table-driven tests that can test all resolver types with the same logic
• Maintain full coverage while reducing code duplication
• Keep resolver-specific tests only where behavior actually differs

Files to Modify

• test/resolver_cache_test.go

References

• Original PR: feat: implement shared cache for bundle, git, and cluster resolvers #9051
• Feedback from @twoGiants requesting this refactoring