Spike : Backend: CI interpolation with arrays

Spike issue for #407176 (closed)

What are the next steps?

• For %16.4, the next steps will be to review and ensure that the performance and security of the method being accessed which is noted in the draft MR: !127255 (closed) will work so we can continue to move forward with this implementation.
• The next steps will be to make the comparison table suggested by @grzesiek in !132045 (comment 1586270684).