[Code Clean] Remove deadcodes about Python3.9 [2/N] (#163627)

As the title stated.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/163627
Approved by: https://github.com/jansel
ghstack dependencies: #163626

cmake/Dependencies.cmake

@@ -821,9 +821,9 @@ if(NOT Python_Interpreter_FOUND)
   message(FATAL_ERROR "Python3 could not be found.")
 endif()
 
-if(${Python_VERSION} VERSION_LESS 3.9)
+if(${Python_VERSION} VERSION_LESS 3.10)
   message(FATAL_ERROR
-    "Found Python libraries version ${Python_VERSION}. Python < 3.9 is no longer supported by PyTorch.")
+    "Found Python libraries version ${Python_VERSION}. Python < 3.10 is no longer supported by PyTorch.")
 endif()
 
 # ---[ Python + Numpy

test/cpp_extensions/open_registration_extension/torch_openreg/pyproject.toml

@@ -12,7 +12,7 @@ name = "torch_openreg"
 version = "0.0.1"
 description = "A minimal reference implementation of an out-of-tree backend"
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 license = { text = "BSD-3-Clause" }
 authors = [{ name = "PyTorch Team", email = "packages@pytorch.org" }]
 dependencies = [

test/dynamo/test_backends.py

@@ -312,7 +312,6 @@ class TestCustomBackendAPI(torch._dynamo.test_case.TestCase):
             mock_group = MagicMock()
             mock_group.names = [name]
             mock_group[name] = mock_3_10
-            # mock_group[name].load.return_value = lambda: "mocked 3.10"
             return mock_group
 
         with patch("importlib.metadata.entry_points", mock_eps):