fix(http): avoid abort a request when fetch operation is completed (#37367)

`abort` method is calling, even if fetch operation is completed

Fixes https://github.com/angular/angular/issues/36537

PR Close #37367

packages/common/http/src/xhr.ts

@@ -339,7 +339,9 @@ export class HttpXhrBackend implements HttpBackend {
         }
 
         // Finally, abort the in-flight request.
-        xhr.abort();
+        if (xhr.readyState !== xhr.DONE) {
+          xhr.abort();
+        }
       };
     });
   }

packages/common/http/test/xhr_spec.ts

@@ -147,6 +147,17 @@ const XSSI_PREFIX = ')]}\'\n';
       });
       factory.mock.mockErrorEvent(new Error('blah'));
     });
+    it('avoids abort a request when fetch operation is completed', done => {
+      const abort = jasmine.createSpy('abort');
+
+      backend.handle(TEST_POST).toPromise().then(() => {
+        expect(abort).not.toHaveBeenCalled();
+        done();
+      });
+
+      factory.mock.abort = abort;
+      factory.mock.mockFlush(200, 'OK', 'Done');
+    });
     describe('progress events', () => {
       it('are emitted for download progress', done => {
         backend.handle(TEST_POST.clone({reportProgress: true}))