Guard test_lapack_empty with has_magma. (pytorch#9936)

Summary:
CUDA lapack functions generally don't work unless has_magma is true.
Pull Request resolved: pytorch#9936

Differential Revision: D9028579

Pulled By: gchanan

fbshipit-source-id: 9b77e3b05253fd49bcabf604d0924ffa0e116055

Author: gchanan

test/test_torch.py

@@ -6394,6 +6394,11 @@ def test_lapack_empty(self):
         devices = ['cpu'] if not torch.cuda.is_available() else ['cpu', 'cuda']
         for device in devices:
 
+            # need to init cuda to check has_magma
+            empty = torch.randn((0, 0), device=device)
+            if device == 'cuda' and not torch.cuda.has_magma:
+                continue
+
             def fn(torchfn, *args):
                 return torchfn(*tuple(torch.randn(shape, device=device) if isinstance(shape, tuple) else shape
                                       for shape in args))