fix: inferStatePrefix... should default to s1 as the first intermediate state.

[alexkeizer]

Description:

We claim in the error that we fall back to s1 as the first intermediate state if we can't infer anything.
However, the implementation actually used s2.

This PR fixes that by setting currentStateNumber := 0 in the fallback case. The off-by-one behaviour is because this number is incremented before it's used to generate a new state.

Testing:

What tests have been run? Did make all succeed for your changes? Was
conformance testing successful on an Aarch64 machine? Yes

License:

By submitting this pull request, I confirm that my contribution is
made under the terms of the Apache 2.0 license.

[bollu]

LGTM, though maybe calling it currentStateNumber isn't the best, how about lastSeenStateNumber? You're the czar of this pat of the repo, so I leave it to you.

[alexkeizer]

LGTM, though maybe calling it currentStateNumber isn't the best, how about lastSeenStateNumber? You're the czar of this pat of the repo, so I leave it to you.

Hmm, it matches the number of the currentState field of the AxEffects, so we'd have to change that one as well to be consistent, and I kind of like the currentState name