Found an issue that was causing types to be completed much more often than they needed to be.

The problem is for lldb_private::Type instances that have encoding types (pointer/reference/const/volatile/restrict/typedef to type with user ID 0x123). If they started out with m_flags.clang_type_resolve_state being set to eResolveStateUnresolved (0), then when we would call Type::ResolveClangType(eResolveStateForward) we would complete the full type due to logic errors in the code. 

We now only complete the type if clang_type_resolve_state is eResolveStateLayout or eResolveStateFull and we correctly upgrade the type's current completion state to eResolveStateForward after we make a forward delcaration to the pointer/reference/const/volatile/restrict/typedef type instead of leaving it set to eResolveStateUnresolved.

llvm-svn: 239752