Optimize __eq__ and __ne__ in key_ordering
Optimize __eq__ and __ne__ in key_ordering

- use `is` when possible before calling `_cmp_key()`

EmreAtes/spack,EmreAtes/spack,tmerrick1/spack,krafczyk/spack,EmreAtes/spack,LLNL/spack,tmerrick1/spack,matthiasdiener/spack,mfherbst/spack,skosukhin/spack,krafczyk/spack,lgarren/spack,EmreAtes/spack,TheTimmy/spack,matthiasdiener/spack,tmerrick1/spack,krafczyk/spack,skosukhin/spack,iulian787/spack,lgarren/spack,EmreAtes/spack,TheTimmy/spack,iulian787/spack,mfherbst/spack,skosukhin/spack,iulian787/spack,matthiasdiener/spack,LLNL/spack,tmerrick1/spack,skosukhin/spack,iulian787/spack,TheTimmy/spack,lgarren/spack,mfherbst/spack,mfherbst/spack,krafczyk/spack,LLNL/spack,TheTimmy/spack,LLNL/spack,TheTimmy/spack,tmerrick1/spack,LLNL/spack,skosukhin/spack,krafczyk/spack,matthiasdiener/spack,lgarren/spack,iulian787/spack,lgarren/spack,matthiasdiener/spack,mfherbst/spack