Add four new tests for error the error handling cases:
- gem_bad_address - store to a bad address, should generate a protection or
page table error
- gem_bad_batch - try to execute a bad batch, should generate a protection,
invalid instruction or page table error
- gem_bad_blit - blit to an invalid location, should generated a protection
or page table error
- gem_hang - hang the GPU on an event that will never happen, test hang
detection & recovery code
