tests: missed one more bit of rollback

Author: feywind

test/table.ts

@@ -1230,6 +1230,10 @@ describe('Bigtable/Table', () => {
       }));
       const stream = table.createReadStream({gaxOptions: {timeout: 2000}});
       stream.on('error', (error: ServiceError) => {
+        assert.strictEqual(error.code, 4);
+        assert.strictEqual(error.message, 'retry me!');
+        assert.strictEqual(requestSpy.callCount, 1); // Ensures the client has not retried.
+        done();
       });
     });
     describe('retries', () => {