Implement resizable stack

[ordinarymath]

This issue is about implementing a resizable stack for CakeML. Currently CakeML's stack size is determined at initial runtime.

[tanyongkiam]

Do you mean resizable memory or only the stack specifically?

CakeML allocates all of its stack/heap memory in one block at the start and manages them.

It might be possible to allow the stack/heap sizes to vary slightly within this block, but doing extra allocation is likely not going to work without a major redesign.