Infinite scroll delay after resume

[jean-moldovan]

Hello!

This is based on: #1990.

In a scenario when you apply a filter to a list of items you would want refresh the list completely by:

          this.$refs.infiniteScroll.reset()
          this.$refs.infiniteScroll.resume()

However, the first poll after resume has 50ms which results in flickering and makes loading state hard to manage.

Example: https://jsfiddle.net/waugrryy/3352/

1. Toggle filter
2. 'No items Available' label is shown for 50ms, bad flickering
3. Spinner is shown

Expected:

1. Toggle filter
2. Spinner is shown right away

Thanks!