Refactor: migrate 5 L2 scene tests to SceneTestCase

[hw-native-sys-bot]

Summary

• Migrate 5 old-style (golden.py + kernel_config.py) tests to SceneTestCase classes
• Move kernel sources from tests/st/ to examples/, delete old golden.py + kernel_config.py
• Add golden/ to pytest pythonpath for shared paged_attention_golden imports

Tests migrated (each verifies a new framework feature):

1. scalar_data_test: multi-output (D.OUT x2), empty kernel signature ([])
2. alternating_matmul_add: int64 scalars, AIC (CUBE) matmul kernel, RTOL=1e-3
3. paged_attention_ringbuffer: RUNTIME_ENV, D.INOUT tensors, bfloat16
4. aicpu_build_graph/paged_attention: aicpu_build_graph runtime, hub kernels
5. host_build_graph/paged_attention: host_build_graph runtime (st version replaces example's small-scale version)

Test plan

• pytest tests/ut -x -q — 149 passed
• pytest --collect-only — 5 new tests collected without errors
• CI: all new tests run on sim platforms

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request transitions the Paged Attention implementation from a small-scale float16 prototype to a production-scale bfloat16 version. Key changes include updating AIC and AIV kernels to support dynamic tile configurations via template dispatch, modifying the orchestration logic to handle larger scales, and introducing a comprehensive suite of tests for various runtimes (aicpu_build_graph, host_build_graph, and tensormap_and_ringbuffer). Additionally, several legacy configuration and golden test files were removed, and the project configuration was updated to include the golden directory in the Python path. I have no feedback to provide as there were no review comments to assess.