Reorganize Test Suite and Consolidate Documentation

[nradakovic]

What

Restructure the toolchain test suite by moving tests from examples/ to a dedicated tests/ directory with clear organization and comprehensive documentation. The refactoring includes:

• Establish tests/ as the primary location for all toolchain validation tests
• Organize tests into feature_verification/ (8 tests) and language_and_standards/ (5 tests)
• Create centralized test documentation in docs/test_suite.md
• Implement platform-aware cross-compilation configuration for improved toolchain compatibility
• Update all CI/CD workflows to reference new test paths

Acceptance Criteria (DoD)

• All 13 tests (8 feature + 5 language/standards) compile and pass on Linux x86_64
• Tests build successfully for cross-compilation targets (aarch64-linux-ebclfsa)
• Comprehensive test documentation exists in docs/test_suite.md with 395+ lines covering:
  • Individual test descriptions and features
  • Feature coverage matrix (34/43 toolchain features)
  • Running instructions for different platforms
  • Cross-compilation guidance
  • Troubleshooting guide
• Test README files simplified with references to centralized documentation
• Root README.md and examples/README.md updated to reflect new structure
• Platform-aware linkstatic configuration using select() statements
  • linkstatic = True only for aarch64-linux-sdk_0.1.0-ebclfsa
  • linkstatic = False (default) for other platforms
• All GitHub Actions workflows updated to use new test paths
• No breaking changes to test execution on supported platforms

How

1. Test Reorganization

   • Create tests/ directory structure with feature_verification/ and language_and_standards/ subdirectories
   • Move all test source files and build configurations from examples/ to appropriate tests/ subdirectories
   • Create comprehensive BUILD files with proper test organization and test_suite grouping

2. Documentation Consolidation

   • Create docs/test_suite.md with complete test documentation (395+ lines)
   • Update individual test README files to contain quick references and links to centralized docs
   • Update root README.md to list test documentation as primary resource
   • Update examples/README.md to indicate tests have moved

3. Cross-Compilation Support

   • Implement platform-aware linkstatic configuration using Bazel select() statements
   • Condition linkstatic behavior on @score_bazel_platforms//:aarch64-linux-sdk_0.1.0-ebclfsa
   • Apply to all cc_library targets: feature_test_lib, pic_test_lib, multifile_lib, whole_archive_lib, pthread_test_lib

4. CI/CD Updates

   • Update .github/workflows/aarch64-ebclfsa.yml to build test targets from tests/ directory
   • Update .github/workflows/aarch64-linux.yml for new test paths
   • Update .github/workflows/autosd.yml for new test paths
   • Update .github/workflows/x86_64-linux.yml for new test paths