[FFI] Make StructuralEqual functor compare tensor content

[pisarev]

Fixes #645.

The StructuralEqual functor calls Equal(lhs, rhs, false, /*skip_tensor_content=*/true), while the StructuralHash functor hashes content (skip_tensor_content = false). The two are used together as the hash and key-equal of the constant de-duplication map in Relax VM codegen (const_dedup_map_ in apache/tvm src/relax/backend/vm/exec_builder.cc). When hash and equal disagree, the map invariant equal(a, b) => hash(a) == hash(b) does not hold, so two distinct constants of equal shape and dtype get merged on a bucket collision and a later op reads the wrong constant.

Which pair collides depends on the STL bucket count, so the same model produces wrong output under MSVC and correct output under libstdc++. The defect is latent on every platform.

This change makes the functor compare content, so it agrees with the hash. Constants that are genuinely equal are still de-duplicated.

Verified on a Windows build (MSVC 19.44, LLVM 18.1.8): after the change, YOLO11n det, YOLO11s cls, PP-OCRv5 det and PP-OCRv5 rec all match onnxruntime to within floating point; before, det and the PP-OCR models were off by 6 to 61 percent relative error.

Full analysis in #645.

[gemini-code-assist]

Code Review

This pull request updates the StructuralEqual::operator() in include/tvm/ffi/extra/structural_equal.h to pass false instead of true as the fourth argument to the Equal function. The reviewer suggests simplifying this call to Equal(lhs, rhs) to leverage default arguments, which improves code readability and avoids the "Boolean Trap" of passing multiple consecutive boolean literals.

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[gemini-code-assist]

Passing multiple consecutive boolean literals (often referred to as the "Boolean Trap") reduces code readability and increases the risk of parameter mismatch errors. Since both map_free_vars and skip_tensor_content default to false in the signature of Equal, we can simplify this call to Equal(lhs, rhs) to make the code cleaner and more maintainable.

    return Equal(lhs, rhs);

[tqchen]

pls fix ci issue