delay data source reads with pending resource ref

[jbardin]

Treat any reference from a data source to a managed resource as a
dependency on the entire resource. While a resource's
attribute may be statically resolvable from the configuration, if the
user added a reference to that resource, it stands to reason that the
user intended there to be a dependency which we need to wait on.

This is an extension of an implicit behavior that existed previously in
Terraform, but was lost in the 0.13 release. That behavior was emergent
from the fact that the Refresh walk did not process the configuration
for managed resources, so any new resources in the config would be
evaluated as entirely unknown during Refresh, even if some attributes
were statically resolvable at that point.

This new implementation restores the old behavior, and extends it to
updates and replacements of the referenced resource. What this does
not add is waiting on transitive dependencies of the referenced
resources. Because the data sources will wait for any changes to the
resources as well, we want to limit the scope to the resources explicitly
listed in the configuration.

Fixes #25961

[codecov]

Codecov Report

Merging #26284 into master will increase coverage by 0.01%.
The diff coverage is 100.00%.

Impacted Files	Coverage Δ
terraform/transform_reference.go	90.78% <100.00%> (+0.39%)	⬆️
states/statefile/version4.go	55.45% <0.00%> (+0.30%)	⬆️
dag/marshal.go	54.79% <0.00%> (+1.36%)	⬆️

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.