core: Call providers' UpgradeResourceState every time
core: Call providers' UpgradeResourceState every time

Previously we tried to short-circuit this if the schema version hadn't
changed and we were already using JSON serialization. However, if we
instead call into UpgradeResourceState every time we can let the provider
or the SDK do some general, systematic normalization and cleanup steps
without always requiring a schema version increase.

What exactly would be fixed up this way is for the SDK to decide, but for
example the SDK might choose to automatically delete from the state
anything that is no longer present in the schema, avoiding the need to
write explicit state migration functions for that common case where the
remedy is always the same.

The actual update logic is delegated to the provider/SDK intentionally so
that it can evolve over time and potentially differ depending on how
each SDK thinks about schema.

apparentlymart/terraform,drebes/terraform,hashicorp/terraform,drebes/terraform,VladRassokhin/terraform,drebes/terraform,pryorda/terraform,ewbankkit/terraform,gechr/terraform,brandontosch/terraform,gechr/terraform,heimweh/terraform,brandontosch/terraform,pradeepbhadani/terraform,brandontosch/terraform,apparentlymart/terraform,VladRassokhin/terraform,apparentlymart/terraform,tommynsong/terraform,ewbankkit/terraform,rnaveiras/terraform,nlamirault/terraform,hashicorp/terraform,tommynsong/terraform,pradeepbhadani/terraform,tommynsong/terraform,brandontosch/terraform,VladRassokhin/terraform,luis-silva/terraform,heimweh/terraform,heimweh/terraform,apparentlymart/terraform,pryorda/terraform,pdecat/terraform,rnaveiras/terraform,luis-silva/terraform,nlamirault/terraform,brandontosch/terraform,ewbankkit/terraform,pdecat/terraform,gechr/terraform,luis-silva/terraform,apparentlymart/terraform,VladRassokhin/terraform,rnaveiras/terraform,luis-silva/terraform,hashicorp/terraform,pradeepbhadani/terraform,ewbankkit/terraform,pryorda/terraform,heimweh/terraform,nlamirault/terraform,pdecat/terraform,drebes/terraform,heimweh/terraform,pdecat/terraform