Don't forbid creating wxSplitterWindow with border style.

Any border specified for wxSplitterWindow was explicitly discarded when
creating it but there doesn't seem to be any reason to forbid it, the original
code probably predated the addition of wxWindow::GetDefaultBorder() which
allowed to have different borders by default for different classes.

In any case, simply remove this code now to allow creating splitters with
borders if so desired.

Closes #12413.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66230 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/splitter.cpp

@@ -94,11 +94,6 @@ bool wxSplitterWindow::Create(wxWindow *parent, wxWindowID id,
     // allow TABbing from one window to the other
     style |= wxTAB_TRAVERSAL;
 
-    // we draw our border ourselves to blend the sash with it
-    style &= ~wxBORDER_MASK;
-    style |= wxBORDER_NONE;
-
-
     if ( !wxWindow::Create(parent, id, pos, size, style, name) )
         return false;