Failing test: http://w3c-test.org/url/urlsearchparams-delete.any.html

Affected code:

    test(function() {
        var url = new URL('http://example.com/?');
        url.searchParams.delete('param1');
        assert_equals(url.href, 'http://example.com/', 'url.href does not have ?');
        assert_equals(url.search, '', 'url.search does not have ?');
    }, 'Removing non-existent param removes ? from URL');

This is the only failing test for URLSearchParams.