Search for ptxas only for cuda backend in supports_tma function (#5314)

For other backends, `ptxas` may not be installed.

Signed-off-by: Anatoly Myachev <[email protected]>

Author: anmyachev

python/triton/_internal_testing.py

@@ -142,11 +142,13 @@ def to_numpy(x):
 
 
 def supports_tma(byval_only=False):
+    if not is_cuda():
+        return False
     _, cuda_version = _path_to_binary("ptxas")
     min_cuda_version = (12, 0) if byval_only else (12, 3)
     cuda_version_tuple = tuple(map(int, cuda_version.split(".")))
     assert len(cuda_version_tuple) == 2, cuda_version_tuple
-    return is_cuda() and torch.cuda.get_device_capability()[0] >= 9 and cuda_version_tuple >= min_cuda_version
+    return torch.cuda.get_device_capability()[0] >= 9 and cuda_version_tuple >= min_cuda_version
 
 
 def tma_skip_msg(byval_only=False):