statedb: avoid getting code from cache

[jsign]

This PR fixes a bug discovered while debugging a test fixture.

[jsign]

The problem appeared in the dumped state for the 2935 contract.
In the post-state, the codeLen encoded in basicData was 0 which made no sense.

After looking, the problem is that obj.code was nil since technically the EVM never called GetCode(...). GetCode(...) actually fills obj.code as a cache.

Since we were accessing the cache directly, we were re-encoding basicdata with length 0 which was wrong.

[jsign]

Normal contract would have already call GetCode(...) in the EVM, so this extra call will simply return it from the cache.

But this will cover for system contracts (like 2935) which update from storage directly as an optimization.

[gballet]

Yeah, I had a feeling this was going to be an issue, which is why I went the route of setting it in update contract code. Should be fixed now, so hopefully that's the end of that story

[jsign]

Note that the consumption of the stable fixtures fails as expected. Remember the reason the job is green is because the consume direct doesn't return -1 yet. It will be fixed in the testing library next release.