Regression test for crbug.com/1140845. Check that a "then" gettter on the object prototype does not crash V8
Evaluating a simple string 'foo' does not cause a crash, but a side-effect exception.
{
    id : <messageId>
    result : {
        exceptionDetails : {
            columnNumber : -1
            exception : {
                className : EvalError
                description : EvalError: Possible side-effect in debug-evaluate
                objectId : <objectId>
                subtype : error
                type : object
            }
            exceptionId : <exceptionId>
            lineNumber : -1
            scriptId : <scriptId>
            text : Uncaught
        }
        result : {
            className : EvalError
            description : EvalError: Possible side-effect in debug-evaluate
            objectId : <objectId>
            subtype : error
            type : object
        }
    }
}
Evaluating a simple string 'foo' with side-effets should give us the string.
{
    id : <messageId>
    result : {
        result : {
            type : string
            value : foo
        }
    }
}