[inductor] fix uncaught exception when checking for openmp on macos (pytorch#141208)

Based on pytorch#133776

Pull Request resolved: pytorch#141208
Approved by: https://github.com/Skylion007

Author: kleinhenz

torch/_inductor/cpp_builder.py

@@ -825,7 +825,7 @@ def is_conda_llvm_openmp_installed() -> bool:
         command = "conda list llvm-openmp --json"
         output = subprocess.check_output(command.split()).decode("utf8")
         return len(json.loads(output)) > 0
-    except subprocess.SubprocessError:
+    except (subprocess.SubprocessError, FileNotFoundError):
         return False