increase memory for e2e tests

Summary:
It is not the first time panoptic instant test fails with memory error:

https://our.intern.facebook.com/intern/fblearner/details/166744913/operator/1735305631/

increasing the memory requirement might fix it.

Reviewed By: rbgirshick

Differential Revision: D19782277

fbshipit-source-id: 9beca005f807c12c5b35cf3e1a3174701e592b10

Author: ppwwyyxx

configs/quick_schedules/panoptic_fpn_R_50_instant_test.yaml

@@ -16,4 +16,4 @@ SOLVER:
   MAX_ITER: 40
   IMS_PER_BATCH: 4
 DATALOADER:
-  NUM_WORKERS: 2
+  NUM_WORKERS: 1