Don't trust the external cache when looking for field descriptors

When looking for field descriptors for a typeref, we should iterate over
every image info available, even those that the cache claimed to have
processed, as a last ditch effort.

rdar://114567246

Author: augusto2112

stdlib/public/RemoteInspection/TypeRefBuilder.cpp

@@ -348,15 +348,23 @@ RemoteRef<FieldDescriptor> TypeRefBuilder::getFieldTypeInfo(const TypeRef *TR) {
     }
   }
 
-  // On failure, fill out the cache, ReflectionInfo by ReflectionInfo,
-  // until we find the field descriptor we're looking for.
+  // If the heuristic didn't work, iterate over every reflection info
+  // that the external cache hasn't processed.
   for (size_t i = 0; i < ReflectionInfos.size(); ++i) {
     if (ExternalTypeRefCache && ExternalTypeRefCache->isReflectionInfoCached(i))
       continue;
     if (auto FD = findFieldDescriptorAtIndex(i, *MangledName))
       return *FD;
   }
 
+  // If we still haven't found the field descriptor go over every reflection
+  // info, even the ones the external cache supposedly processed.
+  // TODO: if we find the field descriptor here there is a bug somewhere (most
+  // likely on the external cache). Log this somehow.
+  for (size_t i = 0; i < ReflectionInfos.size(); ++i)
+    if (auto FD = findFieldDescriptorAtIndex(i, *MangledName))
+      return *FD;
+
   return nullptr;
 }