Move diagnostics to `diagnostics` domain (#24931).

pkg/analysis_server/test/integration/integration_test_methods.dart

Index: pkg/analysis_server/test/integration/integration_test_methods.dart
diff --git a/pkg/analysis_server/test/integration/integration_test_methods.dart b/pkg/analysis_server/test/integration/integration_test_methods.dart
index 5bfce6ac51a2f2d7f0bafeb703c1b700eee94073..24933ef92f1fe5d4c8023c45f9be33690aadf553 100644
--- a/pkg/analysis_server/test/integration/integration_test_methods.dart
+++ b/pkg/analysis_server/test/integration/integration_test_methods.dart
@@ -1637,11 +1637,11 @@ abstract class IntegrationTestMixin {
    *
    *   The list of analysis contexts.
    */
-  Future<ExperimentalGetDiagnosticsResult> sendExperimentalGetDiagnostics() {
-    return server.send("experimental.getDiagnostics", null)
+  Future<DiagnosticGetDiagnosticsResult> sendDiagnosticGetDiagnostics() {
+    return server.send("diagnostic.getDiagnostics", null)
         .then((result) {
       ResponseDecoder decoder = new ResponseDecoder(null);
-      return new ExperimentalGetDiagnosticsResult.fromJson(decoder, 'result', result);
+      return new DiagnosticGetDiagnosticsResult.fromJson(decoder, 'result', result);
     });
   }