Call cycle_fn for every iteration

[MichaReiser]

This PR changes when salsa calls cycle_fn.

Before: Salsa only called cycle_fn when the last provisional and current value were different (this cycle head hasn't converged)

Now: Salsa will call cycle_fn for every iteration

This feels more consistent for a cycle with nested cycles because, before, a query could have converged but kept being executed
because one of the other heads in this cycle hasn't converged yet.

Always calling the cycle_fn also has the benefit that users can use it to finalize the query result.

This also makes CycleRecoveryAction redundant because there's no real difference between Iterate and Fallback. That's why this PR changes the cycle_fn signature to take an owned value and return Self::Output.

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[codspeed-hq]

CodSpeed Performance Report

Merging #1021 will not alter performance

_{Comparing MichaReiser:always-call-cycle-fn (86aa28f) with master (664750a)}

Summary

✅ 13 untouched

[carljm]

Thank you!

[MichaReiser]

I'd appreciate a thumbs up from @mtshiba on this change before merging, considering that it's a breaking change. I, unfortunately, can't request review from you

[mtshiba]

LGTM!