[Compile] Support py38&py39 (#7677) (#7687)

Author: DannyIsFunny

lite/api/python/__init__.py

@@ -18,5 +18,8 @@
 if os.name =='nt':
     current_path = os.path.abspath(os.path.dirname(__file__))
     third_lib_path = current_path + os.sep + 'libs'
-    os.environ['path'] =  third_lib_path+ ';' + os.environ['path']
-    sys.path.insert(0, third_lib_path)
+    try:
+        os.add_dll_directory(third_lib_path)
+    except AttributeError:
+        os.environ['path'] =  third_lib_path+ ';' + os.environ['path']
+        sys.path.insert(0, third_lib_path)