[Testing] Localrunner `run_until_suspension`

Migration from https://github.com/aws/aws-durable-execution-sdk-python-testing/issues/219

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It would be helpful if an alternative method `run_until_suspension` can be provided, which returns when the execution is suspended and users can choose to inspect the history events, interact with callbacks, skip the timers and etc.

_Originally posted by @zhongkechen in https://github.com/aws/aws-durable-execution-sdk-python-testing/pull/192#discussion_r3157449190_

Start by locating the Localrunner implementation and its existing execution methods, then compare the migrated issue and linked discussion for expected suspension behavior. Done means a run_until_suspension entry point returns when execution suspends and allows callers to inspect history, interact with callbacks, and skip timers.

Written by the indexing model from the issue text.