feat: test small losses

[poolpitako]

Here's an edge case of small loss not dropping the debt ratio.
The "root issue" is:

ratio_change: uint256 = min(
            loss * self.debtRatio / self.totalDebt,
            self.strategies[strategy].debtRatio,
        )

min there works like min(int(a), int(b)). if loss is small enough, loss * self.debtRatio / self.totalDebt will be greater than 0 but smaller than 1.

[pandadefi]

I have *** up the rebase so change were lost and the branch got closed.

I have updated the test so that the values used are more simple to read.