Get rid of code duplication in integration tests

[telezhnaya]

I'm referring to integration-tests/src/user/runtime_user.rs, but I guess it's not the only file with code duplications.

Functions get_recursive_transaction_results, get_final_transaction_result and others, were copy pasted from the source code long time ago, changed since then, ofk we forget to update them as well.

It may lead to bugs, it's better to rethink our approach here.