[analysis_server] Move super.dispose() to end of stanim snippet's dis…

…pose method

Equiv change for extension-shipped snippet in Dart-Code/Dart-Code#3965.

Change-Id: Ief61a7d11f19edac6f4f4a14f311d7789add8d80
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/245003
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/lib/src/services/snippets/dart/flutter_snippet_producers.dart

@@ -218,8 +218,8 @@ class FlutterStatefulWidgetWithAnimationControllerSnippetProducer
             returnType: VoidTypeImpl.instance,
             bodyWriter: () {
               builder.writeln('{');
-              builder.writeln('    super.dispose();');
               builder.writeln('    _controller.dispose();');
+              builder.writeln('    super.dispose();');
               builder.writeln('  }');
             },
           );

pkg/analysis_server/test/lsp/completion_dart_test.dart

@@ -2959,8 +2959,8 @@ class _\${1:MyWidget}State extends State<\${1:MyWidget}>
 
   @override
   void dispose() {
-    super.dispose();
     _controller.dispose();
+    super.dispose();
   }
 
   @override

pkg/analysis_server/test/services/snippets/dart/flutter_snippet_producers_test.dart

@@ -211,8 +211,8 @@ class _MyWidgetState extends State<MyWidget>
 
   @override
   void dispose() {
-    super.dispose();
     _controller.dispose();
+    super.dispose();
   }
 
   @override
@@ -263,8 +263,8 @@ class _MyWidgetState extends State<MyWidget>
 
   @override
   void dispose() {
-    super.dispose();
     _controller.dispose();
+    super.dispose();
   }
 
   @override