Promise.map is not a native function (#9562)

* Promise.map is not a native function

Fixes #9557 and adds a test that would have caught it.

* use native map

src/core_plugins/kibana/public/dashboard/__tests__/saved_dashboards.js

@@ -0,0 +1,15 @@
+import ngMock from 'ng_mock';
+import expect from 'expect.js';
+
+describe('SavedDashboards Service', function () {
+  let savedDashboardLoader;
+
+  beforeEach(ngMock.module('kibana'));
+  beforeEach(ngMock.inject(function (savedDashboards) {
+    savedDashboardLoader = savedDashboards;
+  }));
+
+  it('delete returns a native promise', function () {
+    expect(savedDashboardLoader.delete(['1','2'])).to.be.a(Promise);
+  });
+});

src/ui/public/courier/saved_object/saved_object_loader.js

@@ -39,9 +39,13 @@ export class SavedObjectLoader {
 
   delete(ids) {
     ids = !_.isArray(ids) ? [ids] : ids;
-    return Promise.map(ids, (id) => {
-      return (new this.Class(id)).delete();
+
+    const deletions = ids.map(id => {
+      const savedObject = new this.Class(id);
+      return savedObject.delete();
     });
+
+    return Promise.all(deletions);
   }
 
   /**