revert unet trace region size

Author: hschoi4448

models/experimental/functional_unet/tests/common.py

@@ -12,7 +12,7 @@
 UNET_FULL_MODEL_PCC = 0.99840
 UNET_FULL_MODEL_PCC_BH = 0.99780
 
-UNET_TRACE_REGION_SIZE = 540672
+UNET_TRACE_REGION_SIZE = 768 * 1024
 UNET_L1_SMALL_REGION_SIZE = 9344