Fixed the AST importer to ensure that base classes
of Objective-C classes are completed, and that
variables of Objective-C types have their types
completed when the variables are reported.

This fixes a long-standing issue where ivars did
not show up correctly on 32-bit OS X.

<rdar://problem/12184093> 


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@197775 91177308-0d34-0410-b5e6-96231b3b80d8