In the original reproducer design, I expected providers to be more dynamic than they turned out. For example, we don't have any instances where one provider has multiple files. Additionally, I expected there to be less locality between capture and replay, with the provider being defined in one place and the replay code to live in another. Both contributed to the design of the provider info.
This patch refactors the reproducer info to be something static. This means less magic strings and better type checking. The new design still allows for the capture and replay code to live in different places as long as they both have access to the new statically defined info class.
I didn't completely get rid of the index, because it is useful for (1) sanity checking and (2) knowing what files are used by the reproducer.