support both destroy and teardown in custom event handlers

src/generators/nodes/Element.ts

@@ -517,7 +517,7 @@ export default class Element extends Node {
 				`);
 
 				block.builders.destroy.addLine(deindent`
-					${handlerName}.teardown();
+					${handlerName}[${handlerName}.destroy ? 'destroy' : 'teardown']();
 				`);
 			} else {
 				const handler = deindent`

test/js/samples/event-handlers-custom/expected-bundle.js

@@ -212,7 +212,7 @@ function create_main_fragment(component, state) {
 		},
 
 		d: function destroy$$1() {
-			foo_handler.teardown();
+			foo_handler[foo_handler.destroy ? 'destroy' : 'teardown']();
 		}
 	};
 }

test/js/samples/event-handlers-custom/expected.js

@@ -39,7 +39,7 @@ function create_main_fragment(component, state) {
 		},
 
 		d: function destroy() {
-			foo_handler.teardown();
+			foo_handler[foo_handler.destroy ? 'destroy' : 'teardown']();
 		}
 	};
 }