[Backend Tester] Don't run fp64 model tests

ghstack-source-id: 8ced100
ghstack-comment-id: 3256604361
Pull-Request: #13982

Author: GregoryComer

backends/test/suite/models/__init__.py

@@ -22,7 +22,6 @@
 DTYPES: list[torch.dtype] = [
     torch.float16,
     torch.float32,
-    torch.float64,
 ]