Watch mode errors on scope changes after transpilation

[luis-j-soares]

There's an issue with watch mode where field initialisers will trigger diagnostic errors after their scope is transpiled. This only happens after the app has already been transpiled.

Here's a unit test that shows the issue:

it('does not pollute the AST after validation', () => {
    const file = program.setFile<BrsFile>('source/lib.bs', `
        class HasPropertyInitialiser
            name as string = createObject("roString")
            sub new()
                super()
            end sub
        end class
    `);
    program.validate();
    file.transpile();
    program.setFile<BrsFile>('source/another.bs', `
        class AnotherClassJustToInvalidateScope
        end class
    `);
    program.validate();
    expectZeroDiagnostics(program.getDiagnostics());
});