terminal: Terminal Crashes when used with switchable GPU scenario

This is a split/follow on from #1364.

One common case in that massive thread is folks with:

• portable devices that have a discrete GPU and an integrated GPU
• portable devices that have some sort of docking mechanism

Are experiencing issues where the Terminal only works properly on one of the GPUs or is having problems after certain driver updates.

I’m suspecting this is just a reliability problem in the DxRenderer.cpp code, but I don’t have access to any of this type of device.

So this represents:

• Someone with one of these devices and who is experiencing the crash and who is confident in their debugging abilities takes this issue and figures it out. OR
• I (or someone on the team here) eventually gains access to one of these types of devices, repros it, and fixes it.