Constructors are not displayed with the right fixity in Core and native executables

Typing
```
> (2, 3)
```
in the Juvix REPL used to result in the output
```
2, 3
```
Now we get:
```
, 2 3
```
The same in the native executable.

There is a mechanism to remember constructor fixities down the pipeline and then use them for printing in Core and native code. But it seems some changes broke it in the meantime.
