GEN9: igt@testdisplay - incomplete/timeout - slow test

https://intel-gfx-ci.01.org/tree/drm-tip/IGTPW_4440/shard-apl7/igt@testdisplay.html#dmesg-warnings1678

Received signal SIGQUIT.
Stack trace: 
 #0 [fatal_sig_handler+0xd6]
 #1 [killpg+0x40]
 #2 [ioctl+0x7]
 #3 [drmIoctl+0x28]
 #4 [drmModeSetCrtc+0xbe]
 #5 [set_mode+0x568]
 #6 [update_display+0xeb]
 #7 [main+0x2a9]
 #8 [__libc_start_main+0xe7]
 #9 [_start+0x2a]