Files from Fiddle in local directory aren't loaded

[codebytere]

When loading a local fiddle from a directory with multiple files, the Fiddle fails to load and results in missing and/or empty editors:

Probably refs https://github.com/electron/fiddle/pull/1120 - it doesn't look like this actually fixed the problem, since the result in local testing is always an empty array.

cc @dsanders11

[dsanders11]

@codebytere, doing a basic repro test ("Save As", close window, "Open") doesn't repro for me - can you check if this is still a valid issue for you?