Remove support for the keygen tag

third_party/WebKit/LayoutTests/imported/wpt/html/infrastructure/common-dom-interfaces/collections/htmlformcontrolscollection-expected.txt

+This is a testharness.js-based test.
+FAIL The length attribute must return the number of elements in the form assert_equals: The length attribute is incorrect. expected 2 but got 1
+PASS HTMLFormControlsCollection.item(index) must return the indexed item 
+PASS HTMLFormControlsCollection[index] must return the indexed item 
+PASS HTMLFormControlsCollection is not callable 
+PASS HTMLFormControlsCollection[name] must return the named item 
+PASS HTMLFormControlsCollection.namedItem(name) must return the named item 
+PASS The namedItem(name) must return an Element 
+PASS The namedItem(name) must return RadioNodeList 
+PASS The namedItem(name) must return null if the name is empty 
+PASS The namedItem(name) must return null if there is no matched element 
+FAIL Controls can be indexed by id or name attribute assert_equals: Controls can be named by 'id' attribute. expected Element node <keygen id="kg" name="key"></keygen> but got null
+PASS The namedItem(name) must return the items with id or name attribute 
+FAIL The HTMLFormControlsCollection interface is used for collections of listed elements in form element assert_equals: The length should be 8. expected 8 but got 7
+FAIL The HTMLFormControlsCollection interface is used for collections of listed elements in fieldset element assert_equals: The length should be 8. expected 8 but got 7
+PASS The controls in the form element must be sorted in tree order 
+Harness: the test ran to completion.
+