Mouse resizing inverted on floating container

## I'm submitting a…

[x] Bug

[ ] Feature Request

[ ] Documentation Request

[ ] Other (Please describe in detail)

## Current Behavior

When using the mouse to resize a floating container, it shrinks when I want it to grow and vice versa.

## Expected Behavior

Dragging an edge or corner should move that edge or corner in the direction of the dragging.

## Reproduction Instructions

1. Open two windows on a new workspace in a split arrangement.
2. Focus the parent container.
3. Float the parent container.
4. Use the mouse to grab and drag the lower right corner of the container down.
5. Observe that the lower right corner does not move, but the upper left corner moves down instead.

## Environment

Binary i3 version:  4.18.2 (2020-07-26) © 2009 Michael Stapelberg and contributors

Running i3 version: 4.18.2 (2020-07-26) (pid 2923)abort…)

Loaded i3 config: /home/eater/.config/i3/config (Last modified: Thu 17 Sep 2020 11:15:05 AM EDT, 990 seconds ago)


The i3 binary you just called: /usr/bin/i3

The i3 binary you are running: i3

Reproducible with default config

- Linux Distribution & Version: Ubuntu 18.04

- Are you using a compositor (e.g., xcompmgr or compton): No.