[BEAM-14001] Update coder.go unit tests (#16952)
[BEAM-14001] Update coder.go unit tests (#16952)


apache/beam,apache/beam,apache/beam,lukecwik/incubator-beam,chamikaramj/beam,lukecwik/incubator-beam,robertwb/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,chamikaramj/beam,robertwb/incubator-beam,chamikaramj/beam,chamikaramj/beam,apache/beam,robertwb/incubator-beam,robertwb/incubator-beam,robertwb/incubator-beam,chamikaramj/beam,apache/beam,lukecwik/incubator-beam,chamikaramj/beam,chamikaramj/beam,apache/beam,robertwb/incubator-beam,lukecwik/incubator-beam,apache/beam,robertwb/incubator-beam,apache/beam,apache/beam,lukecwik/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,apache/beam,chamikaramj/beam,chamikaramj/beam,apache/beam,chamikaramj/beam,robertwb/incubator-beam,robertwb/incubator-beam,robertwb/incubator-beam,lukecwik/incubator-beam