Properly propagate deps for non-POD structs

Bug #1170 is a bug where a type wasn't deemed movable, and because it
appeared in a vector, that meant misgeneration of code.

Movability calculations are done based on the presence of move
constructors for each field type. This analysis is done in a
depth-first fashion, to ensure that fields of fields are calculated
first. However, this depth-first analysis wasn't working correctly
because we weren't considering all the links in that tree.
Specifically, a type A was considered to depend on its field type
B only for POD structs in the past. It wasn't recognized that
such dependency relationships were required even for a non-POD type A,
in order that this movability/destroyability calculation could
be done correctly for type A.

This change ensures that A always depends on B irrespective of
whether A is POD or non-POD.

This is a fairly significant change to our dependency relationships.

engine/src/conversion/analysis/deps.rs

@@ -37,13 +37,9 @@ impl HasDependencies for Api<FnPrePhase1> {
                 ..
             } => Box::new(old_tyname.iter().chain(deps.iter())),
             Api::Struct {
-                analysis:
-                    PodAnalysis {
-                        kind: TypeKind::Pod,
-                        bases,
-                        field_deps,
-                        ..
-                    },
+                analysis: PodAnalysis {
+                    bases, field_deps, ..
+                },
                 ..
             } => Box::new(field_deps.iter().chain(bases.iter())),
             Api::Function { analysis, .. } => Box::new(analysis.deps.iter()),