taskschd: Add a NULL check to ITaskFolder::GetFolders.

dlls/taskschd/folder.c

@@ -236,6 +236,8 @@ static HRESULT WINAPI TaskFolder_GetFolders(ITaskFolder *iface, LONG flags, ITas
 
     TRACE("%p,%x,%p: stub\n", iface, flags, folders);
 
+    if (!folders) return E_POINTER;
+
     if (flags)
         FIXME("unsupported flags %x\n", flags);
 

dlls/taskschd/tests/scheduler.c

@@ -453,6 +453,9 @@ static void test_FolderCollection(void)
     hr = ITaskFolder_GetFolder(root, Wine, &folder);
     ok(hr == S_OK, "GetFolder error %#x\n", hr);
 
+    hr = ITaskFolder_GetFolders(folder, 0, NULL);
+    ok (hr == E_POINTER, "expected E_POINTER, got %#x\n", hr);
+
     hr = ITaskFolder_GetFolders(folder, 0, &folders);
     ok(hr == S_OK, "GetFolders error %#x\n", hr);