Actions: Remove duplicated input state check

By the time we're processing pointer actions we've
already been through the steps of processing an action
sequence. Within _those_ steps we've already checked
that the input state within the `input state table`
correctly matches expected type for the pointer action.

Address issue #691

Author: shs96c

webdriver-spec.html

@@ -7031,12 +7031,6 @@ <h2>Processing Actions Requests</h2>
   or <code>"pointerCancel"</code> return an <a>error</a> with
   <a>error code</a> <a>invalid argument</a>.
 
- <li><p>If the <a>current session</a>'s <a>input state table</a>
-  already has an entry corresponding to <a>input id</a> <var>id</var>
-  and that entry has a <code>subtype</code> property with value
-  different to <var>subtype</var> return <a>error</a> with <a>error
-  code</a> <a>invalid argument</a>.
-
  <li><p>Let <var>action</var> be an <a>action object</a> constructed
   with arguments <var>id</var>, <code>"pointer"</code>, and
   <var>subtype</var>.