test(loading): add e2e test for loading in tabs and remove animation for basic e2e

references #5426

ionic/components/loading/test/basic/styles.css

@@ -1,3 +1,8 @@
+/* Fix the spinner used in e2e */
+.fixed-spinner svg {
+  animation: none;
+}
+
 .custom-spinner-container {
   position: relative;
   display: inline-block;