Blacklist video and flash acceleration on NVIDIA Linux drivers.
If you create a context when you are low memory, this context may get
into a bad state where geomerty is corrupted and the screen takes seconds
to paint. The context remains in this state until it is destroyed, even
if more memory comes available.
This disabled accelerated compositing to limit the exposure to this bug.
I plan to integrate this into M23. We shouldn't re-enable accelerated
compositing until we have a more robust workaround, or NVIDIA fixes the
context creation bug.