Move the dom directory from web-platform-tests/ to wpt/.

third_party/WebKit/LayoutTests/imported/wpt/dom/nodes/ChildNode-remove.js

 function testRemove(node, parent, type) {
   test(function() {
     assert_true("remove" in node);
     assert_equals(typeof node.remove, "function");
     assert_equals(node.remove.length, 0);
   }, type + " should support remove()");
   test(function() {
     assert_equals(node.parentNode, null, "Node should not have a parent");
     assert_equals(node.remove(), undefined);
     assert_equals(node.parentNode, null, "Removed new node should not have a parent");
@@ skipping 10 matching lines @@
     assert_equals(node.parentNode, null, "Node should not have a parent");
     var before = parent.appendChild(document.createComment("before"));
     parent.appendChild(node);
     var after = parent.appendChild(document.createComment("after"));
     assert_equals(node.parentNode, parent, "Appended node should have a parent");
     assert_equals(node.remove(), undefined);
     assert_equals(node.parentNode, null, "Removed node should not have a parent");
     assert_array_equals(parent.childNodes, [before, after], "Parent should have two children left");
   }, "remove() should work if " + type + " does have a parent and siblings");
 }