Include graphics objects with hidden handles in axes limit calculation (bug #63095). * libinterp/corefcn/graphics.cc (get_children_limits): Get handles to all axes children including those with hidden handle visibility. Add BIST. * libinterp/corefcn/graphics.in.h (text::update_position): Do not automatically change "zliminclude" property. Axes labels are implemented as text objects, and we don't want their extent to be included in the axis limit calculation.

## Test that nested functions with the same name are OK if they are
## defined inside other nested functions with different names.

function retval = duplicate_subfunction_separate_scope_ok ()
  function r = suba ()
    function sub2 ()
      r = 1;
    endfunction
    sub2 ();
  endfunction
  function subb ()
    function sub2 ()
      y = 2;
    endfunction
    sub2 ();
  endfunction
  subb ();
  retval = y + suba ();
endfunction