Disable timer for devices that fail at runtime

Previously the timer would attempt to call the device-specific implementation of any device compiled for regardless of what the RuntimeDeviceTracker says or if it fails. This caused problems when a particular device (such as CUDA) was compiled for but run in a system where the runtime was not available.

Fix this problem by (1) first checking to see if the device is enabled in the RuntimeDeviceTracker before running and (2) if an exception is thrown catch it and disable the device in the RuntimeDeviceTracker.