Lazy loading in free mode may not work

[bcmk]

• Swiper Version: 5d15292
• Platform/Target and Browser Versions: Ubuntu Linux 20.04 / Chrome 88.0.4324.182

What You Did

If both lazy loading and free mode are enabled, lazy loading may not work in some circumstances.
Basically if you move to not loaded yet slides with a mouse and completely stop moving before releasing, slides are not loaded.

I recorded a video showing it: https://youtu.be/zvfhp20sccA.
At first I'm opening a tab with an example built using current master branch of Swiper.
Then I'm opening a tab with the version patched with this proposed change.

Here are examples:
The version from master branch: https://bcmk.github.io/swiper/master.html
Fixed version: https://bcmk.github.io/swiper/fixed.html

Complete examples: https://github.com/bcmk/swiper/tree/lazy-free-fix-example
Look for master.html built from current master (5d15292) and fixed.html built from proposed patch (I'm sending the pull request as well)

Expected Behavior

Talking about provided video, slides number 9 and 10 should be loaded

Actual Behavior

Slides number 9 and 10 were not loaded