Really fix interactive output test compilation in ANSI build.

Use a temporary wxString to make sure the code compiles in both ANSI and STL
versions too.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64945 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

tests/interactive/output.cpp

@@ -377,7 +377,8 @@ void InteractiveOutputTestCase::TestStackWalk()
 #if wxUSE_STACKWALKER
     wxPuts(wxT("*** Testing wxStackWalker ***"));
 
-    StackDump dump(wxTheApp->argv[0].utf8_str());
+    wxString progname(wxTheApp->argv[0]);
+    StackDump dump(progname.utf8_str());
     dump.Walk();
 
     wxPuts("\n");