[MergeFunctions] Replace all uses of unnamed_addr functions.

This reduces code size for constructs like vtables or interrupt
tables that refer to functions in global initializers.

Differential Revision: https://reviews.llvm.org/D34805

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315852 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed