Remove "basic STL functionality" configure and CMake checks

This check didn't work in configure when using C++17 or later, as
std::bind2nd() is removed in C++17 and so was worse than useless as it
actually prevented --enable-stl from working.

And while it was only done when using C++98 in CMake, it still seems
pretty useless there too as there should be no environments in which
basic stuff like std::vector<> or std::find_if() is not available.

So just remove it entirely.

configure

@@ -20706,46 +20706,6 @@ $as_echo "$as_me: WARNING: No std::iostreams, switching to --disable-std_iostrea
 fi
 
 if test "$wxUSE_STL" = "yes"; then
-        { $as_echo "$as_me:${as_lineno-$LINENO}: checking for basic STL functionality" >&5
-$as_echo_n "checking for basic STL functionality... " >&6; }
-if ${wx_cv_lib_stl+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <string>
-            #include <functional>
-            #include <algorithm>
-            #include <vector>
-            #include <list>
-int
-main ()
-{
-std::vector<int> moo;
-             std::list<int> foo;
-             std::vector<int>::iterator it =
-                 std::find_if(moo.begin(), moo.end(),
-                              std::bind2nd(std::less<int>(), 3));
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_cxx_try_compile "$LINENO"; then :
-  wx_cv_lib_stl=yes
-else
-  wx_cv_lib_stl=no
-
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $wx_cv_lib_stl" >&5
-$as_echo "$wx_cv_lib_stl" >&6; }
-
-    if test "$wx_cv_lib_stl" != yes; then
-         as_fn_error $? "Can't use --enable-stl as basic STL functionality is missing" "$LINENO" 5
-    fi
-
         { $as_echo "$as_me:${as_lineno-$LINENO}: checking for compliant std::string::compare" >&5
 $as_echo_n "checking for compliant std::string::compare... " >&6; }
 if ${wx_cv_func_stdstring_compare+:} false; then :