SSAO from depth (recreating normals) doesn't work on android

SSAO from depth is recommended on mobile platforms to avoid a depth+normals prepass. Problem is that that path is currently broken on Android:

Steps to reproduce:

1. Download the repro project
2. Build it to android

Axpected:
Intense ambient occlusion in the general area of where the cube and plane intersect

Actual:
A big part of the plane receives SSAO artifacts that are spatially unstable