Support PyTorch 2.12 compatibility

[Fatemanx]

Summary

• Update AOT cache loading and saving for PyTorch 2.12 AOTCompiledFunction.
• Remove old PyTorch behavior fallbacks from focused tests.
• Update requirements and docs for the torch 2.12.x test environment, including CUTLASS/ninja testing.

Relates to #43

Test Plan

• git diff --check
• python -m pip check
• pytest -q tests/feature_tests/test_compile_artifacts.py tests/feature_tests/test_piecewise_deferred_assert_scope.py tests/feature_tests/test_unbacked_symbol_guard.py tests/feature_tests/test_symbolic_unification.py tests/feature_tests/test_transformer_cache_reuse.py tests/torch_native_tests/test_inductor_cache_reuse.py tests/api_tests/test_nested_compile.py
  • 58 passed, 6 skipped
• MAGI_CUTLASS_ROOT=<cutlass-root> pytest -q tests/feature_tests/test_matmul_epilogue_fusion.py
  • 28 passed, 4 skipped

[cennn]

Hi @Fatemanx, thanks for the effort on PyTorch 2.12 compatibility — your changes gave us a solid head start.

We've built on top of your work and landed full PT 2.12 support (along with a containerized CI pipeline covering both PT 2.9 and PT 2.12) in #55, which has now been merged.

Closing this PR since the changes are superseded, but feel free to open new PRs on the latest main if you spot anything or want to contribute further. Thanks again!