inference: look for `:terminate_globally` override in backedge termination check (#44106)
Now we can "fix" #41694:
```julia
Base.@assume_effects :terminates_globally function issue41694(x)
res = 1
1 < x < 20 || throw("bad")
while x > 1
res *= x
x -= 1
end
return res
end
@test fully_eliminated() do
issue41694(2)
end
```