Fix an issue with the rooting of animating nodes

[mrobinson]

Make sure nodes removed from map of rooted animating nodes are rooted on
the stack before triggering event handlers. We also make sure not to
call from_untrusted_node_address on nodes that aren't guaranteed to be
rooted.

Fixes #26498.

---

• ./mach build -d does not report any errors
• ./mach test-tidy does not report any errors
• These changes fix #26498.
• There are tests for these changes

[highfive]

Heads up! This PR modifies the following files:

• @asajeffrey: components/script/script_thread.rs
• @KiChjang: components/script/script_thread.rs

[highfive]

Warning

• These commits modify script code, but no tests are modified. Please consider adding a test!

[mrobinson]

This is a flaky crash, so there isn't a solid guarantee that this fixes the issue. I tried to be as careful as possible when confirming this though. Before this change the following test:

./mach test-wpt   /_mozilla/mozilla/transitionend_safety.html --repeat 100

always resulted in at least one crash. After the change, I could not reproduce the crash at all.

[jdm]

Thanks for investigating and figuring out a way to manually test it!
@bors-servo r+

[bors-servo]

📌 Commit c4a38be has been approved by jdm

[bors-servo]

⌛ Testing commit c4a38be with merge 9eee048...

[bors-servo]

☀️ Test successful - status-taskcluster
Approved by: jdm
Pushing 9eee048 to master...