Replace assert_null and assert_not_null with assert_equals and assert_not_equals.
Replaced assert_not_undefined and assert_not_null with assert_not_equals.
Also changed the expected result for cloneNode() as its default value has been changed from true to false.
Merge pull request #442 from rniwa/remove_assert_null_from_parsing_html_templates

Replace assert_null and assert_not_null with assert_equals and assert_not_equals.