Fix fileName options passed to babylon (#4570)

The filename options used by babylon is called `sourceFilename` and not `filename`. Therefore the option should be adjusted to be called `sourceFilename`.

packages/babel-core/src/transformation/file/index.js

@@ -53,6 +53,7 @@ export default class File extends Store {
       nonStandard:   this.opts.nonStandard,
       sourceType:    this.opts.sourceType,
       filename:      this.opts.filename,
+      sourceFileName:this.opts.filename,
       plugins:       []
     };