Clean up aux column generator for stack overflow table

[bobbinth]

This PR cleans up a little auxiliary column code generator for the stack overflow table.

Specifically:

• Moved some functions inline when the body of a function contains just a single function call.
• Used OverflowTableRow::to_value() method to compute aux request/responses.
• Removed OverflowTable.update_trace field since it is no longer needed.

We can further simplify the OverflowTable struct by not tracking all overflow table rows and instead tracking only current ones. But I didn't do this in this PR.

[plafer]

LGTM! Left a suggestion for a future PR

[plafer]

Ideally there would be only one type for clock cycles. save_current_state() (and self.trace) still use u64 for clock cycles, while the rest uses Felt (presumably because Felt doesn't implement Ord which is needed for BTreeMap. This would probably justify the need for a ClockCycle type (in another PR)

[bobbinth]

It's a bit tricky here. Usually, clock cycles should be u32 values as we can't execute more than $2^{32}$ cycles on the VM (actually, the limit it $2^{29}$ cycles). And this is how we treat them in rest of the VM. So, if we add a ClockCycle type, we should make it based on u32.

However, for stack initialization purposes we need to use "negative cycles". That is, we initialize the overflow tables as if some values were pushed into it before the program started executing. So, if there is one value in the stack overflow table before the program starts running, the clock cycle for that value would be set to -1 or in our filed this would be MODULUS - 1 - which is a u64 value. So, here we need to use u64s and Felts.

[Al-Kindi-0]

Looks great and thank you for fixing the typo!