500% increase CPU usage when app goes to background

[olegus199]

Bevy version

0.10.1

[Optional] Relevant system information

iMac 27 late 2012, core i7, NVIDIA GeForce GTX 675MX 1GB, 24GB RAM, macOS Catalina 10.15.7

What you did

I noticed that Bevy consumes massive amount of CPU when going to background when I focus on the another window (VS code, for instance)
This is normal load of 59% of CPU. Bevy window is focused

This is abnormal load of 284.8% of CPU. VS code is focused, Bevy on the background

[mockersf]

duplicate of #8080 and #5856