Fix typo in _.debounce unit test.

Former-commit-id: b8138dbae144836701e65f98de8981defaaa1a54

test/test.js

@@ -710,7 +710,7 @@
     });
 
     asyncTest('should work with `maxWait` option', function() {
-      var limit = 128,
+      var limit = 100,
           withCount = 0,
           withoutCount = 0;