Sporadic panics on WeakMap tests

[jedel1043]

So, apparently our CI has some sporadic panics on the following tests:

• test/built-ins/WeakSet/prototype/delete/delete-entry-initial-iterable.js
• test/built-ins/WeakSet/prototype/has/returns-false-when-object-value-not-present.js

However, I tried to reproduce it in my pc without success, so a platform dependent bug maybe?

Build environment:

• OS: Arch Linux x86_64
• Version: 6.2.7-arch1-1
• Target triple: x86_64-unknown-linux-gnu
• Rustc version: rustc 1.68.0 (2c8cc3432 2023-03-06)

[langston-barrett]

Potentially related to #2670.

[jedel1043]

Found a more reliable reproduction of the issue:

let list = []

for (let i = 0; i < 35; i++) {
  list.push(list);
}

let ws = new WeakSet(list);

This snippet always panics for me, which seems to imply that the cause of this is a garbage collection pass within a borrow.