Enable comparisons between Union and builtin

[nielstron]

Is your feature request related to a problem? Please describe.
The following program does not compile with an error

from opshin.std.fractions import *
from typing import Dict, List, Union

def validator(a: int, b: Union[int, Anything]) -> bool:
    return a==b

Traceback (most recent call last):
  File "/Users/niels/miniconda3/envs/opshin/bin/opshin", line 6, in <module>
    sys.exit(main())
             ^^^^^^
  File "/Users/niels/git/opshin/opshin/__main__.py", line 523, in main
    perform_command(args)
  File "/Users/niels/git/opshin/opshin/__main__.py", line 353, in perform_command
    raise err from None
  File "test.py", line 5
    return a==b
          ^
NotImplementedError: Comparison Eq for int and Any is not implemented. This is likely intended because it would always evaluate to False.
Note that opshin errors may be overly restrictive as they aim to prevent code with unintended consequences.

Describe the solution you'd like
It is possible for elements of these types to be equal. This would involve casting the operator on the left to Anything and then comparing.

Note that b == a does also not work.

Describe alternatives you've considered
None