Use wxDELETE() and wxDELETEA() when possible.

Use wxDELETE[A]() functions which automatically NULL out their arguments after
deleting them instead of doing it manually.

Closes #9685.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64656 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/regtest/regtest.cpp

@@ -1031,8 +1031,7 @@ void RegTreeCtrl::TreeNode::OnCollapse()
 {
     DestroyChildren();
 
-    delete m_pKey;
-    m_pKey = NULL;
+    wxDELETE(m_pKey);
 }
 
 void RegTreeCtrl::TreeNode::Refresh()