[Sema] Re-parent AccessorDecls for local vars too

Make sure we walk into any non-DeclContext decl,
allowing us to e.g walk into VarDecls to correctly
re-contextualize their accessors in an outer
autoclosure. I don't *think* this currently makes
much of a difference since the mangling today uses
the DeclContext of the VarDecl, but it seems like
the right thing to do regardless.

Author: hamishknight

lib/Sema/TypeCheckStmt.cpp

@@ -173,7 +173,10 @@ namespace {
         D->setDeclContext(ParentDC);
       });
 
-      return Action::VisitNodeIf(isa<PatternBindingDecl>(D));
+      // Only recurse into decls that aren't themselves DeclContexts. This
+      // allows us to visit e.g initializers for PatternBindingDecls and
+      // accessors for VarDecls.
+      return Action::SkipNodeIf(isa<DeclContext>(D));
     }
   };