Steps to reproduce the bug:

1. Click generate_garbage() to run a heavy computation that allocates alot of heap memory
2. Click perform_major_gc() to trigger garbage collection
3. Click generate_garbage() again and then you'll probably see an error in browser console, press print_stderr() to see more relevant error messsage
4. In case the error did not reproduce try repeating the steps 1-3

When I perform described steps, one of the observed errors looks as following: