Bytecode compare runs with two-stage compilation

[cameel]

Similar to #13583, we should have a bytecode compare run to ensure that two-stage compilation produces output identical to compiling everything in one go.

We're especially interested in the pattern where the optimization is only performed in the second step, that we will be recommending as a way to parallelize compilation. Such compilation should not only produce the same bytecode but also metadata.

Currently two-stage compilation is covered only by the ~via_ir_equivalence test, but if this pattern is to become more widespread, we need more confidence that there are no issues with it. Also, this command-line test does compilation in the first stage, which is not exactly the same pattern. We might actually want to extend that test to cover more patterns.