Slow the page a lot when too much component

[timothee-durand]

We have a page with a lot of component (between 2000 and 10000 mounted components), it stays performant until we open the inspector with vue devtools, and then everything is very slow, sometimes the page is even blocked.

[edimitchel]

Still there in v7, already there in v6 (vuejs/devtools-v6#1875)