Set event.LiveFired to undefined in specialSubmit handler so that click events...

Set event.LiveFired to undefined in specialSubmit handler so that click events bound before the submit won't prevent the submit to fire. Fixes #6359

src/event.js

@@ -706,6 +706,7 @@ if ( !jQuery.support.submitBubbles ) {
 					var elem = e.target, type = elem.type;
 
 					if ( (type === "submit" || type === "image") && jQuery( elem ).closest("form").length ) {
+						e.liveFired = undefined;
 						return trigger( "submit", this, arguments );
 					}
 				});
@@ -714,6 +715,7 @@ if ( !jQuery.support.submitBubbles ) {
 					var elem = e.target, type = elem.type;
 
 					if ( (type === "text" || type === "password") && jQuery( elem ).closest("form").length && e.keyCode === 13 ) {
+						e.liveFired = undefined;
 						return trigger( "submit", this, arguments );
 					}
 				});