[ThinLTO] Clean up stale alias import handling
Summary:
Remove some code that was no longer needed. The first FIXME is
stale since we long ago started using the index to drive importing,
rather than doing force importing based on linkage type. And
now with r309278, we no longer import any aliases.
Reviewers: dblaikie
Subscribers: inglorion, llvm-commits
Differential Revision: https://reviews.llvm.org/D37266
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312019
91177308-0d34-0410-b5e6-
96231b3b80d8