i965: Skip IR annotations with INTEL_DEBUG=noann.

Running shader-db with INTEL_DEBUG=noann reduces the runtime
from ~90 to ~80 seconds on my machine. It also reduces the disk space
consumed by the .out files from 660 MB (676 on disk) to 343 MB (358 on
disk).

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/drivers/dri/i965/intel_debug.c

@@ -65,6 +65,7 @@ static const struct dri_debug_control debug_control[] = {
    { "blorp", DEBUG_BLORP },
    { "nodualobj", DEBUG_NO_DUAL_OBJECT_GS },
    { "optimizer", DEBUG_OPTIMIZER },
+   { "noann", DEBUG_NO_ANNOTATION },
    { NULL,    0 }
 };