Make VarDecl::isLayoutExposedToClients check property wrappers more lazily

The check for "has property wrappers" as part of determining whether the
layout of a variable is exposed to clients can trigger reference
cycles. Push this check later, which eliminates these cycles for types
that aren't frozen/fixed-layout.

This is a hack, not a real fix, but it eliminates the cyclic
references observed in rdar://112079160.

Author: DougGregor

lib/AST/Decl.cpp

@@ -2079,19 +2079,23 @@ bool VarDecl::isLayoutExposedToClients() const {
   if (!parent) return false;
   if (isStatic()) return false;
 
-  if (!hasStorage() &&
-      !getAttrs().hasAttribute<LazyAttr>() &&
-      !hasAttachedPropertyWrapper()) {
-    return false;
-  }
 
   auto nominalAccess =
     parent->getFormalAccessScope(/*useDC=*/nullptr,
                                  /*treatUsableFromInlineAsPublic=*/true);
   if (!nominalAccess.isPublic()) return false;
 
-  return (parent->getAttrs().hasAttribute<FrozenAttr>() ||
-          parent->getAttrs().hasAttribute<FixedLayoutAttr>());
+  if (!parent->getAttrs().hasAttribute<FrozenAttr>() &&
+      !parent->getAttrs().hasAttribute<FixedLayoutAttr>())
+    return false;
+
+  if (!hasStorage() &&
+      !getAttrs().hasAttribute<LazyAttr>() &&
+      !hasAttachedPropertyWrapper()) {
+    return false;
+  }
+
+  return true;
 }
 
 /// Check whether the given type representation will be