Allow resetting globalState.options #1805

We are using oapi-codegen as a library to split out client operation code by tags into separate files. However, it is currently impossible to do this in a single running process due to globalState being shared across each Generate operation. When I try to generate separate files by calling Generate multiple times, only the first set of operations are included, and the rest do not have any operations.

I wonder if being able to reset the global state options as needed would be helpful here to support more deterministic behavior.