Merge pull request #33065 from 3405691582/StdlibModule_NotJustLinux

[test] Invert stdlib_dir conditional sense.

Author: CodaFi

test/lit.cfg

@@ -1441,10 +1441,10 @@ config.substitutions.append(('%target-sdk-name', config.target_sdk_name))
 
 # Add 'stdlib_dir' as the path to the stdlib resource directory
 stdlib_dir = os.path.join(config.swift_lib_dir, "swift")
-if platform.system() == 'Linux' or platform.system() == 'Windows':
-    stdlib_dir = os.path.join(stdlib_dir, config.target_sdk_name, run_cpu)
-else:
+if platform.system() == 'Darwin':
     stdlib_dir = os.path.join(stdlib_dir, config.target_sdk_name)
+else:
+    stdlib_dir = os.path.join(stdlib_dir, config.target_sdk_name, target_arch)
 config.substitutions.append(('%stdlib_dir', stdlib_dir))
 
 # Add 'stdlib_module' as the path to the stdlib .swiftmodule file