bug: class transpiling modifies AST

Transpiling a class sometimes modifies the AST. Here's a unit test:

it.only('does not mess with AST when injecting `super()` call', async () => {
    const file = program.setFile('source/classes.bs', `
        class Parent
        end class

        class Child extends parent
            sub new()
                super()
            end sub
        end class
    `);
    expect(
        (file.ast as any).statements[1].body[0].func.body.statements[0].expression.callee.name.text
    ).to.eql('super');
    await program.transpile([], program.options.stagingFolderPath);
    expect(
        (file.ast as any).statements[1].body[0].func.body.statements[0].expression.callee.name.text
    ).to.eql('super');
});

Start with the unit test shown in the issue and trace the class transpilation path reached by program.transpile. Verify that injecting the super() call does not mutate the existing AST, and keep the test passing with the callee name still reported as super after transpilation.