[operators] Harden transpose-nd against overflow, divide-by-zero, and null pointers - #11334

Summary

This PR hardens the transpose operator implementation in src/operators/transpose-nd.c against arithmetic overflow, division-by-zero, out-of-bounds indexing, and null pointer dereferences:

1. Creation Validation (create_transpose_nd):
   • Validates that transpose_op_out != NULL.
2. Reshape Validation (reshape_transpose_nd):
   • Validates that transpose_op != NULL, input_shape != NULL, and perm != NULL.
   • Protects total tensor elements (num_elements) and total byte size (total_bytes) calculations against size_t overflow with xnn_safe_mul.
   • Protects input_stride and output_stride bounds check calculations (stride[i] * shape[i] and current_stride) with xnn_safe_mul to prevent integer wrapping that could bypass the stride validation checks.
   • Validates that xnn_normalize_transpose_permutation succeeds and returns normalized_dims > 0, avoiding undefined behavior and underflow of normalized_dims - 1 in subsequent indexing.
3. Tile Computation Safety:
   • Validates normalized_element_size != 0 before computing tile count, preventing division by zero.
   • Enforces minimum tile sizes (max(1, ...)) to prevent division by zero in subsequent tile aspect calculations.
4. Setup Validation (setup_transpose_nd):
   • Validates that input != NULL and output != NULL.

Testing

• Added unit regression tests in test/operators/transpose-nd.cc covering null pointer outputs, invalid reshape parameters (zero dims, oversized dims, null arrays, overflow shapes, duplicate/out-of-bounds permutations), and null setup pointers.
• All 35 tests in transpose-nd-test and all 18 transpose-related tests in ctest pass cleanly.