Handle standard JSON translation with `outputSelection` for `=<0.4.19`

We've come across an issue while recompiling a contract with `0.4.19` as laid out here: https://github.com/ethereum/sourcify/issues/1017

TLDR: The compiler gives empty JSON output without throwing because the `outputSelection` fields were introduced in `0.4.18` and updated in `0.4.19`.

I believe the `outputSelection` field needs to be handled by the JSON translator [translate.ts](https://github.com/ethereum/solc-js/blob/master/translate.ts) of `solc-js` for the earlier versions.

Start in translate.ts and trace how outputSelection is translated for Solidity compiler versions 0.4.18 and 0.4.19. Confirm the empty JSON output case described in the issue, then verify that earlier compiler versions handle standard JSON translation with outputSelection without throwing or producing empty output.

Written by the indexing model from the issue text.