Removed a test using an obsolete attribute

This test is using .olderShadowRoot which has been removed from the
spec. Therefore this test is obsolete.
These tests are using an obsolete attribute

These tests are using .olderShadowRoot which has been removed from the
spec. Therefore these are obsolete.
Merge pull request #589 from KenjiBaheux/obsolete-tests-using-oldershadowroot

Removed tests using an obsolete attribute