Add op batch flags to decoder trace

[bobbinth]

This PR adds op batch flags to the decoder trace and makes a coupe of other small updates:

• Add 3 op_batch_flag columns to the decoder trace.
• Update the logic for how number of operation groups in the span is computed, and make related changes to trace generation.
• Update the logic of how in_span flag is populated in the decoder trace.
• Updated program hash computations to make them consistent between Script and execution trace.

[grjte]

Looks good! I left a few small things inline and one question about possibly unifying some span-related stuff to make it easier to keep track of how all the different things are related.