Issue 651769: 9 failing web-platform-tests for Selection that pass in Firefox and Edge

http://w3c-test.org/selection/addRange.html
http://w3c-test.org/selection/collapse.html
http://w3c-test.org/selection/collapseToStartEnd.html
http://w3c-test.org/selection/deleteFromDocument.html
http://w3c-test.org/selection/extend.html
http://w3c-test.org/selection/interfaces.html
http://w3c-test.org/selection/isCollapsed.html
http://w3c-test.org/selection/removeAllRanges.html
http://w3c-test.org/selection/selectAllChildren.html

These failures need analysis, but may point to low-hanging fruit for improving interop. Judgement is required, the failures may be entangled with spec issues.

See  issue 651572  for the source of this data, which includes failing subtests.

Note: Results may have changed in the interim.