test(es/compat): Add a test for optional chaining with loose mode

[komyg]

Description:
Fix: #7559

Related issue (if exists):
#7561

[komyg]

Hey @kdy1, I've added a test for this transformation in loose mode.

However, the generated code is different. In the loose mode, I get this:

 class Foo {
     #x;
     test() {
         this == null ? void 0 : this.y.#x;
     }
 }

Instead of what we were getting without the loose mode:

class Foo {
    #x;
    test() {
        this === null || this === void 0 ? void 0 : this.y.#x;
    }
}

Is the loose output correct, if so I can update the test to reflect that.

However, please note that in the original issue, @jridgewell said that the problem was that we were not transforming the #x private field correctly. The expected output (according to him) is:

var id = 0;
function _class_private_field_loose_key(name) {
    return "__private_" + id++ + "_" + name;
}
var _x = _class_private_field_loose_key("_x");
class Foo {
    test() {
        this?.y[_x];
    }
    //…
}

[kdy1]

@komyg

 class Foo {
     #x;
     test() {
         this == null ? void 0 : this.y.#x;
     }
 }

This is the expected output.

And the private field transform is correct. See https://play.swc.rs/?version=1.3.72&code=H4sIAAAAAAAAA1NIzkksLlZwy89XqOblUgAB5QprKKsktbhEQxMuARbKyCxWsLVVyCvNyVGwVyjLz0xRMFCwAovrVeoh9NYC6VoAk2gqxF4AAAA%3D&config=H4sIAAAAAAAAA1VPuw7DIAzc8xXIc4c2Q4f%2BQz8CUSei4iXsSEVR%2Fr0QIGkXY9%2F5fMc6CAFvUvAQa27zEGQkjMecEUqO5ScjwCkgqagDw6WzTIWapCGs2FYfYBln5CJDGq%2FjrUnAeE%2BYYY5LU4DVTk%2Fp11N5GyIS%2FZ8uq9LNBjt8Gu4FrH8tO9s%2BUwLXBHc4l7rbcRk0PbuyxBq2L%2FGqRBEYAQAA

[komyg]

Great, @kdy1!

I would like to merge this test if you agree. Could you review the PR, please?

[kdy1]

swc-bump:

• dbg-swc