Fix #10717, .trigger("load") on images can't bubble to window.

This means no manually triggered event named "load" can bubble, so avoid that name for delegated custom events.

src/event.js

@@ -566,6 +566,11 @@ jQuery.event = {
 			setup: jQuery.bindReady
 		},
 
+		load: {
+			// Prevent triggered image.load events from bubbling to window.load
+			noBubble: true
+		},
+
 		focus: {
 			delegateType: "focusin",
 			noBubble: true

test/unit/event.js

@@ -1155,6 +1155,25 @@ test(".trigger() bubbling on disconnected elements (#10489)", function() {
 	jQuery( window ).off( "click" );
 });
 
+test(".trigger() doesn't bubble load event (#10717)", function() {
+	expect(1);
+
+	jQuery( window ).on( "load", function(){
+		ok( false, "load fired on window" );
+	});
+
+	// It's not an image, but as long as it fires load...
+	jQuery( '<img src="index.html" />' )
+		.appendTo( "body" )
+		.on( "load", function() {
+			ok( true, "load fired on img" );
+		})
+		.trigger( "load" )
+		.remove();
+
+	jQuery( window ).off( "load" );
+});
+
 test("jQuery.Event( type, props )", function() {
 
 	expect(5);