simplify module expansion eval
simplify module expansion eval

Make the expansion logic easier to follow, keeping the evaluation and
registration local to switch cases. We don't validate anything between
count or for_each (config loading should handle that), and we don't need
to keep relying on the count == -1 sentinel value.

rnaveiras/terraform,apparentlymart/terraform,VladRassokhin/terraform,ewbankkit/terraform,pryorda/terraform,rnaveiras/terraform,pryorda/terraform,pdecat/terraform,heimweh/terraform,heimweh/terraform,pryorda/terraform,pdecat/terraform,VladRassokhin/terraform,tommynsong/terraform,pdecat/terraform,ewbankkit/terraform,ewbankkit/terraform,pdecat/terraform,VladRassokhin/terraform,VladRassokhin/terraform,tommynsong/terraform,apparentlymart/terraform,heimweh/terraform,rnaveiras/terraform,apparentlymart/terraform,heimweh/terraform,hashicorp/terraform,apparentlymart/terraform,heimweh/terraform,hashicorp/terraform,apparentlymart/terraform,ewbankkit/terraform,hashicorp/terraform,tommynsong/terraform