Implement wxRegion::Equal() for wxOSX.

As there doesn't seem to be any native functions for comparing HIShapes,
compute their differences to find out if they are equal.

Closes #13339.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@68280 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -441,6 +441,10 @@ All (GUI):
 
 - Support float, double and file name values in wxGenericValidator (troelsk).
 
+OSX:
+
+- Implement wxRegion::Equal() (Dr.Acula).
+
 GTK:
 
 - Generate events for two auxiliary mouse buttons in wxGTK (Marcin Wojdyr).