feat(ts) migrate TestUtils to TS

modules/util/TestUtils.js → modules/util/TestUtils.ts

  * @param {number} [advanceTimer] - the value to be passed to Jasmine clock's tick method.
  * @returns {Promise<void>}
  */
-export function nextTick(advanceTimer) {
-    advanceTimer && jasmine.clock().tick(advanceTimer);
+export function nextTick(advanceTimer?: number): Promise<void> {
+    if (advanceTimer) {
+        jasmine.clock().tick(advanceTimer);
+    }
 
     return new Promise(resolve => process.nextTick(resolve));
 }