Pushbuild fixes: 
 - Make MAX_SEL_ARGS smaller (even 16K records_in_range() calls is 
   more than it makes sense to do in typical cases)
 - Don't call sel_arg->test_use_count() if we've already allocated 
   more than MAX_SEL_ARGs elements. The test will succeed but will take
   too much time for the test suite (and not provide much value).