Update on "[WIP][CI] Move CPU-only jobs to xenial"

Differential Revision: [D16862005](https://our.internmc.facebook.com/intern/diff/D16862005)

This will give us diff signal for CPU-only builds with FBGEMM enabled, ensuring quantization gets timely signal

Built on top of #24795 (thanks @kostmo!)

Author: James Reed

.circleci/cimodel/data/pytorch_build_definitions.py

@@ -14,7 +14,7 @@
 
 DOCKER_IMAGE_PATH_BASE = "308535385114.dkr.ecr.us-east-1.amazonaws.com/pytorch/"
 
-DOCKER_IMAGE_VERSION = 327
+DOCKER_IMAGE_VERSION = 331
 
 
 @dataclass