Fix #7472 and added test for #3113

- Forms with an input that has either name="action" or name="some-other-attr-on-the-form" caused problems in IE6/7.  This is fixed.

- Changed check in $.attr for ret === null to typeof ret === "object" to catch any inputs that are accidentally retrieved in IE6/7, since attributes cannot be set to objects and typeof null === "object"

test/index.html

@@ -203,6 +203,7 @@ Z</textarea>
 			<select name="D4" disabled="disabled">
 				<option selected="selected" value="NO">NO</option>
 			</select>
+			<input name="id">
 		</form>
 		<div id="moretests">
 			<form>