Defer loading any pending update records until we've finished deserializing.
This fixes a bug where an update record causes us to load an entity that refers
to an entity we've not finished loading yet, resulting in badness.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@207603 91177308-0d34-0410-b5e6-96231b3b80d8