tests fix

[SantiagoGregory]

The issue in testFlow() is that the pranks aren't handled correctly. Just switch to this and it passes:

        vm.startPrank(alice);
        pool.withdraw(pool.QUOTE_INDEX(), uint32(quoteAmount));
        vm.stopPrank();
        
        vm.startPrank(bob);
        pool.withdraw(pool.BASE_INDEX(), uint32(baseAmount));
        vm.stopPrank();