Remove unneeded syscall_counter

[THenry14]

Closes #20

Introduced changes

• Remove unneeded syscall_counter and code relevant to it

Checklist

• Linked relevant issue
• Updated relevant documentation
• Added relevant tests
• Performed self-review of the code
• Added changes to CHANGELOG.md

[ksew1]

LGTM

[ksew1]

I had an afterthought that maybe it is not worth creating ExecutionResources since it only holds VmExecutionResources. Perhaps we should just use this directly? Or do we want to leave some room in case we want to add other fields to ExecutionResources in the future?

[THenry14]

I had an afterthought that maybe it is not worth creating ExecutionResources since it only holds VmExecutionResources. Perhaps we should just use this directly? Or do we want to leave some room in case we want to add other fields to ExecutionResources in the future?

Yes, so the plan is to extend this soon-ish, but it wasn't the main reason to do that this way. Having this encapsulated actually follows the layout of the versioned constants file from the sequencer, and ExecutionResources is aimed to hold values parsed from it.