Web Platform Tests

• mathml/presentation-markup/fractions/frac-created-dynamically-*.html They should use for numbers, they should use reftest-wait and modify content after page load + forcing a reflow.

• presentation/mo-paint-lspace-rspace.html Remove it from WebKit https://github.com/web-platform-tests/wpt/pull/15948

• mathml/presentation-markup/spaces/mspace-children.html Remove it from WebKit https://github.com/web-platform-tests/wpt/pull/15722

• mathml/relations/html5-tree/href-click-3.html Make it work in WebKit (https://bugs.webkit.org/show_bug.cgi?id=187039) or Gecko (https://bugzilla.mozilla.org/show_bug.cgi?id=1530110). https://github.com/web-platform-tests/wpt/pull/15530