Draft: SCORU/Tests: Ensure refutation happens in refutation tests

Context

There is an issue (#3653 (closed)) with the WASM pvm refutation tests, where the loser mode of the rollup node is ineffective and so there are no refutations to be made. This MR makes sure that there is a refutation game being played in the tests.

Manually testing the MR

The tests for the arith PVM should work:

dune exec tezt/tests/main.exe -- -f sc_rollup.ml refutation arith

The tests for the WASM PVM should not:

dune exec tezt/tests/main.exe -- -f sc_rollup.ml refutation wasm_2_0_0 -k