Extremely slow compilation

[arnetheduck]

nim --profilevm of nimbus beacon node:

    19262402  10011904  /nimbus-eth2/vendor/nim-stew/stew/shims/macros.nim(91, 6)
    16058290    162922  /nimbus-eth2/beacon_chain/spec/datatypes/base.nim(923, 6)
     7518182   4432438  /nimbus-eth2/vendor/nim-chronos/chronos/internal/asyncmacro.nim(16, 6)
     6637539    149648  /nimbus-eth2/vendor/nim-stew/stew/shims/macros.nim(188, 6)
     6585929    366897  /nimbus-eth2/vendor/nim-stew/stew/shims/macros.nim(163, 6)
     5847740     95469  /nimbus-eth2/vendor/nim-stew/stew/shims/macros.nim(239, 7)
     5803038   1410058  /nimbus-eth2/vendor/nim-stew/stew/shims/macros.nim(210, 6)

https://github.com/status-im/nim-stew/blob/master/stew/shims/macros.nim#L91 is used extensively by this library - listing fields in objects this way is slow in the VM.