Reduce allocations in ToMultidimensionalArray

[alexzzzs]

Optimizes the ToMultidimensionalArray method to reduce memory allocations when deserializing multidimensional arrays.

The Issue

The previous implementation of CopyFromJaggedToMultidimensionalArray created a new int[] array at every step of the recursion to store indices. For large multidimensional arrays (e.g., 3D grids), this resulted in O(N) intermediate array allocations, creating unnecessary GC pressure.

The Fix

• Replaced the recursive array creation with a single int[] buffer allocated once at the entry point.
• This buffer is passed down the recursion stack and updated in-place.
• Updated JaggedArrayGetValue to accept a length parameter, allowing it to read from the shared buffer without needing a trimmed copy.