When dynamically-typed attributes are in the schema, we use different
conventions for representing nested blocks containing them (using tuples
and objects instead of lists and maps).
The normalization code here doesn't deal with those because the legacy
SDK never generates them, but we must still pass them through properly or
else other SDKs will be blocked from using dynamic attributes.
Previously this function would panic in that situation. Now it will just
pass through nested blocks containing dynamic attribute values entirely
as-is, with no normalization whatsoever. That's okay, because the scope
of this function is only to normalize inconsistencies that the legacy
SDK is known to produce, and the legacy SDK never produces dynamic-typed
attributes.
Now that we have an opt-out to let the legacy SDK return values that are
inconsistent with the new conventions for representing configuration,
various parts of Terraform must now be prepared to deal with
inconsistencies.
This function normalizes the most egregious inconsistencies relating to
the representation of nested blocks, freeing any recipient of its result
from worrying about these inconsistencies itself.
Martin Atkins