Backtracking in the Yul optimizer

Depends on https://github.com/ethereum/solidity/issues/13719.

Slowly evaluate introducing backtracing in the Yul optimizer.
First candidates would be optimizing functions in isolation to evaluate the merits of specializing functions (see e.g. https://github.com/ethereum/solidity/issues/13787) or even inlining in general.

Start by reading dependency issue #13719 and the referenced function-specialization discussion in issue #13787. Investigate the Yul optimizer's options for evaluating functions in isolation, specialization, or inlining; done means assessing and documenting the merits of introducing backtracking.

Written by the indexing model from the issue text.