Combine similar converter tests + lint test files

[Gerrit0]

Every directory in src/test/converter is a separate test. Even for trivial tests like the variable test that only have 3 lines, we have to re-start the TypeScript compilation, so these tests take at least a couple seconds. Quite a few of these tests could be combined. I think we should be able to get the test running time down to under a minute, I'd really like to get it down to 30 seconds or less, but I'm not sure if that's possible without sacrificing test organization.

Further, most of the test files currently do not pass TSLint rules, when rebuilding the tests, this should be fixed to avoid IDE warnings.

[Gerrit0]

Resolved by 1fd2185