ThinLTO: Move the ODR resolution to be based purely on the summary.

This is a requirement for the cache handling in D18494

Differential Revision: http://reviews.llvm.org/D18908

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266519 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed