Try to fix build on Windows and tests on macOS.

Author: serhiy-storchaka

Lib/test/test_sys.py

@@ -2091,6 +2091,8 @@ def test_remote_exec_bytes(self):
         self.assertEqual(stderr, b"")
 
     @unittest.skipUnless(os_helper.TESTFN_UNDECODABLE, 'requires undecodable path')
+    @unittest.skipIf(sys.platform == 'darwin',
+                     'undecodable paths are not supported on macOS')
     def test_remote_exec_undecodable(self):
         script = '''
 print("Remote script executed successfully!")

Python/sysmodule.c

@@ -2498,9 +2498,7 @@ sys_remote_exec_impl(PyObject *module, int pid, PyObject *script)
         Py_DECREF(path);
         return NULL;
     }
-    Py_BEGIN_ALLOW_THREADS
     DWORD attr = GetFileAttributesW(debugger_script_path_w);
-    Py_END_ALLOW_THREADS
     PyMem_Free(debugger_script_path_w);
     if (attr == INVALID_FILE_ATTRIBUTES) {
         DWORD err = GetLastError();