Workarounds for running tests against wasm rebuilds of old compilers.

[ekpyron]

@axic I used this branch for running the solc-js tests against the wasm rebuilds now... additionally I patched compiler.js on the fly to replace 'latest' with the respective version string...

Making this a draft, since we'll probably need to discuss if and how this should end up in master.

[axic]

@ekpyron ah we're not testing the CLI with different versions though.

[ekpyron]

Not in the "normal" solc-js test suite... what I do in https://github.com/ethereum/solidity/blob/98ec970813c47ebbb3ad9b11042116de5b89aac5/scripts/wasm-rebuild/docker-scripts/rebuild_tags.sh#L158 (part of ethereum/solidity#8118) is to copy the "new old" soljson.js over to test it - that's how I noticed that they don't run without these changes.

But yeah: we need to decide what to do about this - if we make the CLI tests compatible with old versions, then we should probably always run them against old versions as well...

Related to this: I'd also vote for making it possible to run the test suite against one particular soljson.js version, resp. even better against a particular file only without needing to edit the test suite for it.

[ekpyron]

Not sure how difficult it would be to let the npm/tape stuff take a soljson.js file as optional argument or something like that... my experience with them is only tangential...