Silence some error output in the presence of multi-step commands

I am calling wasm-merge, wasm-metadce, and wasm-opt in sequence and the output of the first two steps both errors with "Some VMs may not accept this binary because it has a large number of locals in function". I think it makes sense to silence this error with some flag that implies that the result isn't final or that there are further optimizations that will be applied.

I'm not confident if this is the only type of error that it makes sense to do something like this and how special-cased the solution might be.

Start by tracing the diagnostics emitted by wasm-merge, wasm-metadce, and wasm-opt for the large-locals warning. Determine whether a flag should suppress this warning for intermediate outputs or whether broader diagnostic handling is needed; done means the intended multi-step workflow avoids the unwanted errors without hiding final-result warnings.