Make matrix layout invariants compile-time

[GopalakrishnanN]

Description

• Make fixed-rank Position arithmetic, factories, and row/column layout mapping usable in constant expressions.
• Enforce positive coordinate ranks, same-rank conversions, and nonnegative static matrix dimensions at compile time.
• Fix the three-dimensional make_Position overload to construct Position<3> instead of converting from Position<2>.
• Add compile-time assertions for coordinate operations and layout mappings, plus a runtime smoke test for dynamic coordinates.

Motivation and Context

The matrix layout helpers describe fixed-rank metadata, but their invariants and arithmetic were previously evaluated at runtime. In addition, the three-dimensional factory constructed a two-dimensional position and converted it to rank three, which could read a nonexistent third element from the source.

Moving these operations and constraints to compile time catches invalid layouts during compilation while preserving the existing runtime API and generated layout arithmetic.

Validation:

• .venv\Scripts\lintrunner.exe -a onnxruntime/core/util/matrix_layout.h onnxruntime/test/common/matrix_layout_test.cc
• cmake --build build/Windows/RelWithDebInfo --config RelWithDebInfo --target onnxruntime_test_all --parallel 8
• onnxruntime_test_all.exe --gtest_filter="MatrixLayoutTest.*" (1 test passed)

[Copilot]

Pull request overview

This PR strengthens core/util/matrix_layout.h by making fixed-rank coordinate/layout helpers usable in constant expressions and by moving key invariants (positive ranks, nonnegative static dimensions, same-rank conversions) to compile-time checks. It also fixes the make_Position 3D factory to actually construct a Position<3> and adds compile-time + runtime tests to validate the behavior.

Changes:

• Make Position, MatrixShape, and row/column-major layout helpers constexpr where applicable, and add compile-time invariant checks (static_assert).
• Fix make_Position(T,T,T) to return Position<3, T, L> directly (avoiding the prior rank-mismatch conversion path).
• Add compile-time assertions and a small runtime smoke test covering layout mapping for runtime coordinates.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
onnxruntime/core/util/matrix_layout.h	Converts core coordinate/layout utilities to constexpr and enforces key invariants at compile time; fixes 3D make_Position.
onnxruntime/test/common/matrix_layout_test.cc	Adds compile-time assertions for Position/layout behavior plus a runtime coordinate mapping smoke test.