test fixes

Summary: Some random seed changes. Skip multigpu tests when there's only one gpu. This is a better fix for what AI is doing in D80600882.

Reviewed By: MichaelRamamonjisoa

Differential Revision: D80625966

fbshipit-source-id: ac3952e7144125fd3a05ad6e4e6e5976ae10a8ef

tests/test_knn.py

@@ -72,6 +72,7 @@ class TestKNN(TestCaseMixin, unittest.TestCase):
         factors = [Ns, Ds, P1s, P2s, Ks, norms]
         for N, D, P1, P2, K, norm in product(*factors):
             for version in versions:
+                torch.manual_seed(2)
                 if version == 3 and K > 4:
                     continue
                 x = torch.randn(N, P1, D, device=device, requires_grad=True)