Planar reflections do not work in OpenGL4

This is not a regression as it occurs in 4.16.2

The test case was just recently updated to test for planar reflections so not sure if this is intended to work or not.

1. Open QAGame in the editor
2. Navigate to Edit -> Project Settings -> Engine - Rendering
3. Enable "Support global clip plane for Planar Reflections"
4. Close the editor
5. Launch QAGame using

   UE4Editor.exe QAGame -game -windowed -OpenGL4 -log
   

6. Hit '~' and enter "Open TM-ShaderModels"
7. Navigate to the Planar Reflections room

Result: Floor is not reflecting the room above it

Expected: Floor is reflecting the room above it