Prevent FakeDvalFound Errors

[StachuDotNet]

Context: a FakeDval is a value that we use to represent another concept (errorrails, runtime errors, blanks).

We're getting increasingly more Exception of type 'LibExecution.Errors+FakeDvalFound' was thrown. rollbars lately.

These are raised by 2 separate situations; there are relevant TODOs here:

• a fakeval in the SQLCompiler
  • [ ] update code to ignore these
• a fakeval that emerges from another function
  • [ ] update code to make a note of what functions generate these
  • [ ] consider deprecating the function causing it

Neither of those is super concerning / high priority, but they're noise, and might happen often enough to page us and possibly wake us sometime.

[StachuDotNet]

Relevant (now-muted) rollbar: https://rollbar.com/darkops/darklang/items/3385

[pbiggar]

Fakevals are gone as of #5085