Modify snapshot function representation of classes

[david-yz-liu]

Given the following code:

def f() -> None:
    my_type = int
    print(snapshot_to_json(snapshot()))

if __name__ == '__main__':
    f()

the JSON output contains the expanded __dict__ of the int class as the "value" of the object. We should modify this behaviour so that when recursing on type instances, the snapshot function just shows the repr of the type, e.g. (<class 'int'>), rather than expanding the __dict__.