BFCache is blocked by weblocks even if they are released.

[Szczepan Bielecki (Pimko)]

Describe the bug: 

BFCache is blocked by weblocks even if they are released.  

 

Steps To Reproduce issue: 

On simple demo https://weblock-bfcache-test.glitch.me/  

1. Open simple demo 
2. Click the link “Google.pl” 
3. Click the back browser button, 
4. Check DevTools -> Application -> Back/Forward cache there should be the reason why BFCache was not restored: BrowsingInstanceNotSwapped (Sometimes Unknown) 

 
Expected behavior: 
BFCache will be not, blocked by the released locks. 

Additional context: 
According to https://groups.google.com/a/chromium.org/g/bfcache-dev/c/M0-n4TrFyCM/m/hv7PY7rqAQAJ 
There is a mention about releasing the lock and not blocking the bfcache.