Make the type-checking of the standard library working without diagnostic issues when the current file contains some compiler-synthesized builtin conformances

[tothambrus11]

This is a bit tricky. When viewing a source file from the standard library, e.g. ``, we have some error diagnostics outputted because the type checker somehow fails to realize that it's the standard library it's inspecting. We should understand what's going in with creating the Program containing the standard library, and reproduce it with a unit test. This could be then debugged easier or shown to Dimi.