do not panic if there is no deposed state

NodeDestroyDeposedResourceInstanceObject should not panic if the deposed
state no longer exists.

terraform/node_resource_destroy_deposed.go

@@ -159,6 +159,11 @@ func (n *NodeDestroyDeposedResourceInstanceObject) Execute(ctx EvalContext, op w
 		return diags.Append(err)
 	}
 
+	if state == nil {
+		diags = diags.Append(fmt.Errorf("missing deposed state for %s (%s)", n.Addr, n.DeposedKey))
+		return diags
+	}
+
 	change, destroyPlanDiags := n.planDestroy(ctx, state, n.DeposedKey)
 	diags = diags.Append(destroyPlanDiags)
 	if diags.HasErrors() {

terraform/node_resource_destroy_deposed_test.go

@@ -176,3 +176,28 @@ aws_instance.foo: (1 deposed)
   Deposed ID 1 = i-abc123
 	`)
 }
+
+func TestNodeDestroyDeposedResourceInstanceObject_ExecuteMissingState(t *testing.T) {
+	p := simpleMockProvider()
+	ctx := &MockEvalContext{
+		StateState:           states.NewState().SyncWrapper(),
+		ProviderProvider:     simpleMockProvider(),
+		ProviderSchemaSchema: p.ProviderSchema(),
+		ChangesChanges:       plans.NewChanges().SyncWrapper(),
+	}
+
+	node := NodeDestroyDeposedResourceInstanceObject{
+		NodeAbstractResourceInstance: &NodeAbstractResourceInstance{
+			Addr: mustResourceInstanceAddr("test_object.foo"),
+			NodeAbstractResource: NodeAbstractResource{
+				ResolvedProvider: mustProviderConfig(`provider["registry.terraform.io/hashicorp/test"]`),
+			},
+		},
+		DeposedKey: states.NewDeposedKey(),
+	}
+	err := node.Execute(ctx, walkApply)
+
+	if err == nil {
+		t.Fatal("expected error")
+	}
+}