All symlinked files are ignored

## Issue

All files that are symlinked are ignored by relay-compiler.

This includes files found via `src` in single project repos and `generatedSources` in multi project repos

This means that while its common to exclude `"**/node_modules/**"`, if you dont want to, and use pnpm (which uses symlinks) its impossible for relay to discover your files

## Expected behaviour

Either by default, or via a flag, relay compiler sees and resolves symlinked files as if they were standard files