fix: make sure setTimeout exists on global (#400)

Author: tomanagle

src/helpers.js

@@ -5,7 +5,9 @@ const globalObj = typeof window === 'undefined' ? global : window
 // Currently this fn only supports jest timers, but it could support other test runners in the future.
 function runWithRealTimers(callback) {
   const usingJestFakeTimers =
-    globalObj.setTimeout._isMockFunction && typeof jest !== 'undefined'
+    globalObj.setTimeout &&
+    globalObj.setTimeout._isMockFunction &&
+    typeof jest !== 'undefined'
 
   if (usingJestFakeTimers) {
     jest.useRealTimers()