Pass wxWANTS_CHARS to the wxRichTextCtrl constructor in the unit tests.

Fixes test failures caused by the return key being used for dialog navigation.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73413 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775