fix: Pass through sourcemaps

[timfish]

I was testing sourcemap pass through support and found an issue!

The added test case results in the following error:

✖ produces a valid sourcemap when an inputSourceMap is provided (0.819125ms)
  TypeError [Error]: Converting circular structure to JSON
      --> starting at object with constructor 'State'
      |     property 'mapping' -> object with constructor 'Object'
      --- property 'generated' closes the circle
      at JSON.stringify (<anonymous>)
      at SourceMapGenerator.SourceMapGenerator_validateMapping [as _validateMapping] (/orchestrion-js/node_modules/source-map/lib/source-map-generator.js:298:50)
      at SourceMapGenerator.SourceMapGenerator_addMapping [as addMapping] (/orchestrion-js/node_modules/source-map/lib/source-map-generator.js:110:12)
      at State.map (/orchestrion-js/node_modules/astring/dist/astring.js:1203:26)
      at State.writeAndMap (/orchestrion-js/node_modules/astring/dist/astring.js:1179:12)
      at Object.ClassDeclaration (/orchestrion-js/node_modules/astring/dist/astring.js:515:11)
      at Object.ExportNamedDeclaration (/orchestrion-js/node_modules/astring/dist/astring.js:625:34)
      at Object.Program (/orchestrion-js/node_modules/astring/dist/astring.js:234:27)
      at generate (/orchestrion-js/node_modules/astring/dist/astring.js:1250:29)
      at Transformer.transform (/orchestrion-js/lib/transformer.js:143:20)

[bizob2828]

you have a linting error but LGTM